Academic ResearchCaloriesObesityPublic Health

The Calorie Theory – prove it or lose it

This is extracted from: “The Obesity Epidemic: What caused it? How can we stop it?”

During June and July of 2009 I approached the British Dietetic Association (BDA), Dietitians in Obesity Management (DOM), the National Health Service (NHS), the National Institute for Clinical Excellence (NICE), the Department of Health (DoH), the National Obesity Forum (NOF) and the Association for the Study of Obesity (ASO) to ask all of these expert organisations for proof of the 3,500 formula (also known as the calorie theory).

British Dietetic Association (BDA)

On 10 June, I sent the following query to the BDA: “I am doing some research on obesity and I would be most grateful if you could help me. Please can you explain where the ‘One pound of fat contains 3,500 calories…’ comes from?”

I received a prompt and pleasant reply, “Unfortunately we do not hold information on the topic that you have requested.” It was suggested that I contact a dietitian. I happened to be with several dietitians at an obesity conference later that month, so I asked fellow delegates and no one knew where the 3,500 formula came from. No one knew where the ‘eatwell’ plate proportions came from. One dietitian said to me “You’ve made us think how much we were just ‘told’ during our training, with no explanation. A group of us over there don’t even know where the five-a-day comes from.” (This may help)


So, after the conference, on 29 June, I sent the following email to the NHS: “I am an obesity researcher and I am trying to find out the rationale behind the statement: “One pound of fat contains 3,500 calories, so to lose 1lb a week you need a deficit of 500 calories a day”. This specific reference is a verbatim quotation from the British Dietetic Association’s Weight Loss Leaflet Want to Lose Weight and keep it off? The BDA reply was ‘we do not hold information on the topic.’ As this formula is the foundation of all current weight loss advice, it is critical to be able to prove it. Please can you let me know where this formula comes from and the evidence for it?”

On 30 June I received another prompt reply: “Unfortunately our Lifestyles team do not hold this information and are unable to assist you with your enquiry. I would suggest you contact the Department of Health to see if they can help.”

On 1 July I forwarded the email exchange with the NHS to the Department of Health. I had to chase on 6 July and then got a response saying they would get back to me within 20 working days. Meanwhile, I had also written to NICE (1 July) and they responded on 2 July saying they would get back to me within a maximum of 20 working days.

National Obesity Forum (NOF)

On 2 July I sent the same email to the NOF and the ASO and received a very prompt email back from the NOF (two hours later) suggesting that I contact the ASO. I thanked the NOF for this, but pointed out that their own web site quoted the 3,500 formula verbatim and also had the following classic example: “one less (sic) 50 calorie plain biscuit per day could help you lose 5lbs (2.3kg) in a year – and one extra biscuit means you could gain that in a year!” I have heard nothing back from the NOF since. I sent Dr. David Haslam, NOF chair, an email on 6 July attaching An Essay on Obesity, which I had written, for his interest and comment. On 10 July I also sent Dr. Haslam the exchange I had had with the ASO, so that information could be shared.

Association for the Study of Obesity (ASO)

The ASO response was the most helpful by far, but it still completely failed to prove the 3,500 formula. My query was circulated to board members and two kindly replied:

One reply was: ”Basic biology tells us that 1kg pure fat, converted to energy = 9000 kcal, 1lb pure fat = 0.453 kg = 4077 kcal. The approximation to 3500 kcal is made on the basis that ‘adipose tissue’ is not 100% fat (some water and some lean tissue). Hence to lose 1lb pure fat = 4077 kcal deficit, or 1lb fat tissue in the body = approx 3500kcal deficit. This equates to 500kcal per day to lose 1lb in a week. This has been supported by numerous studies using whole body calorimetry.” There were no sources put forward, for these “numerous studies”. I asked on 21 July and again on 11 August for “even one obesity study that proves this formula” and have received nothing back.

You can make 1lb = 2,843 calories or 3,752 calories without much effort. (This error could have a weight impact of a two stone loss or a six stone gain each year if any of this nonsense were true.) (Please see footnote for calculation).

The ASO member uses the word “approximation”, as do many references to the calorie formula, so there may be some acknowledgement of the number of variables. However, the diet advice that follows takes no account of this word “approximation”. If we take just one variation – the difference between 3,555 and 3,500 equates to five to six pounds a year (footnote). The NOF cautions that eating, or not eating, one biscuit a day could cause a person to gain, or lose, five pounds in a year. Well, the formula being inaccurate can also do this without any biscuit involvement at all. In fact, if 3,555 is correct and not 3,500 (notwithstanding the fact that there is no proof for either formula), this would have made a difference of 172 pounds over the past 30 years (the obesity epidemic period). Fortunately the error would be ‘in our favour’ so we should have all been able to eat nearly 11,000 biscuits and get away with it, or be over 12 stone lighter.

The second reply from the ASO was ‘evidence’ from NICE and a web link to the full NICE document Management of obesity: Full Guidance, December 2006. The specific proof offered was one study (Table 15.14) of 12 subjects, given a deficit of 600 calories a day, where the outcome was “a change of approximately -5 kg (95% CI -5.86kg to -4.75kg, range -0.40 kg to -7.80 kg) compared with usual care at 12 months. Median weight change across all studies was approximately -4.6 kg (range -0.60 kg to -7.20 kg) for a 600 kcal deficit diet or low-fat diet and +0.60 kg (range +2.40 kg to -1.30kg) for usual care”.

So, let me understand this, the people on the 600 calorie-a-day deficit (the NICE recommendation) were 5 kilograms (11 pounds) lighter than those not doing this “at 12 months.” Applying the basic maths formula, these 12 people should each have lost 600*365/3,500 = 62.57 pounds of fat. Not an ounce (of fat) more or less. AND, there should have been no range of results – everyone should have lost exactly the same (that’s what happens with a mathematical formula). The least anyone lost (let’s put it all into pounds) was 0.8 pounds and the most anyone lost was 17.2 pounds. Even the highest weight loss was 45 pounds lower than it should have been. This is also all about fat – we haven’t even started looking at muscle or water loss. This is also a study of 12 people. There are 1.1 billion overweight people in the world and we can’t prove a formula using 12 of them.

There were 15 other studies in Table 15.14, 10 of which had data for where a calorie deficit had been created over a specified period of time. This enabled me to analyse what the weight loss should have been (using the 3,500 formula) and what the average weight loss actually was (from the study data). Again, in every single study, there was a wide range of results (which means that the formula failed per se). In all of the other ten studies, the actual weight loss was multiples away from what the weight loss should have been. The smallest gap between actual weight loss and ‘should have happened’ weight loss (according to the formula) was 28.7 pounds (we continue to ignore water to try to give the formula a chance). At the other extreme, the biggest difference between the fat that should have been lost and the fat that was lost was 143.9 pounds.

Department of Health (DoH)

I was still digesting the immense implications of all this when the DoH reply arrived, on the 21 July, saying “The Department is unaware of the rationale behind the weight formula you refer to.” Pause for a second – the UK government Department of Health, has no idea where their founding piece of diet advice comes from. They kindly suggested another lead, (Dietitians in Obesity Management UK (DOM UK) – a specialist group of the British Dietetic Association), which I followed up on 24 July.

National Institute of Clinical Excellence (NICE)

I chased NICE on 27 July, as the 20 working days were ‘up’ in my calendar. I appeared to have been passed between NHS and NICE during July and a helpful woman called me back to say she had found the right department to deal with the query. A couple of days later, the reply came “Whilst our guidance does contain reference to studies involving 500 calorie deficit diets we do not hold any information about the rationale behind the statement ‘one pound of fat contains 3,500 calories, so to lose 1lb a week you need a deficit of 500 calories a day’.” That is to say – although we are an evidence based organisation, we have no evidence.

Dieticians in Obesity Management (DOM)

On 10 August I received a response from DOM UK: “I have asked our members and this answer was returned. It’s a mathematical equation, 1gram of fat is 9kcal, therefore 1kg fat equals 9000kcal. There are some losses but 1 lb of fat is approximately 4500kcal divide that by 7 days and its (sic) approximately 643kcal hence the deficit.” I went back to DOM UK, on the 10 August, to request an answer to the second part of the calorie theory – if that is how 600 calories is derived (and I have never before seen the 3,500 become 4,500), how can we then say with such confidence that each and every time this deficit is created one pound will be lost.

On the 18 August, I received a reply from one of the DOM UK Committee members: “My understanding is that it comes from the thermodynamics of nutrition, whereby one lb of fat is equivalent to 7000kcals, so to lose 1 lb of fat weight per week you would need an energy deficit of 7000kcals per week, or 500kcals a day. In or around that, depending on whether or not you use metric system and your clinical judgement, some people use a deficit of 600kcals a day and others 500kcals a day. There is good evidence that this level of deficit produces weight differences of approx 5kg at 1 year.”

This time the 3,500 deficit ‘needed’ has doubled to ‘7,000’ calories. Or, to put it another way, one pound of fat has become 7,000 calories. You can start to see what I have experienced as a researcher – how widely this formula is used as fact and yet how little it is understood and how few people know how to use their own ‘fact’.

So, in the example from Dietitians in Obesity Management, key proponents of the calorie formula, one year of a 600 calorie a day deficit will produce a weight loss of approximately 11 pounds – not the 62.5 pounds of fat alone that should be yielded.

When I pointed this out and suggested “I really think we need to fundamentally review the basis of current diet advice and stop saying ‘to lose 1lb of fat you need to create a deficit of 3500 calories’”, the final reply I got was “I guess a key to all of this is that weight loss doesn’t appear to be linear, any more than weight gain is.”

At last, an admission that the formula has no basis of fact.

The organisations approached have been helpful and accessible, but none is able to explain where the 3,500 comes from, let alone to provide evidence of its validity.

A request

I have a simple and reasonable request. I would like proof of this formula – that it holds exactly every single time – or I would like it to be banished from all dietary advice worldwide.

Any proof needs to source the origin of the formula. Then the proof needs to hold in all cases. There needs to be overwhelming, irrefutable and consistent evidence that each and every time a deficit of 3,500 calories is created, one pound of fat is lost.

Since, we already have overwhelming evidence that such proof cannot be provided, it is not enough that we quietly stop using this formula – it is too widely assumed to be true for us to just sweep it under the carpet. We need to issue a public statement saying that it does not hold and should not be used again. We need to tell people that they will not lose one pound of fat for every deficit of 3,500 calories that they create. We need to tell people that there is no formula when it comes to weight loss and we have been wrong in giving people the hope that starvation will lead to the loss of 104 pounds each and every year, in fat alone.


This calculation is done as follows: It assumes that a person can maintain weight at a daily intake of the calories assumed to equal one pound of fat. If we think one pound equals 3,500 calories and in fact one pound equals 2,843 calories, over a year, 657 ‘extra’ calories a day, simply from the formula ‘being wrong’, would add up to 239,805 extra calories and this, divided by 2,843 gives 84 pounds, or six stone. Adjust the calculations for women more typically maintaining at 2,000 calories a day and men more typically at 2,600 calories a day and the inaccuracy of the formula still creates wide disparity.

161 thoughts on “The Calorie Theory – prove it or lose it

  • The caloric hypothesis has NO PREDICTIVE POWER. It is a dead horse in the world of science.

  • I’m not sure if anyone has brought this up, but I just wanted to point out a flaw in the statement “The difference between 3,555 and 3,500 could result in the loss of 5 to 6 pounds per year”. That is not correct. the 3,500 guideline is set as a weekly calorie deficit, not a daily one. In order to come up with 5 to 6 pounds, you would need to multiply the 55 calorie increase by 365 to come to 20,075 calories. This results in roughly 5.7 pounds if you assume 3,500 calories/lb. But since the 3,500 is based off a weekly deficit, not a daily one, the difference only would result an extra 55 calories * 52 weeks/year which is 2,860. This is slightly more than half a pound.

    My point, I think the 3500 calories is still a very good estimate, assuming the 9kcal/lb of fat is accurate.

    • Hi Al
      There’s a footnote in the book, which explains how the calculations were done. I’ll add it on asap.

      Under the sub heading “Association for the study of obesity” – this is written: “You can make 1lb = 2,843 calories or 3,752 calories without much effort. (This error could have a weight impact of a two stone loss or a six stone gain each year if any of this nonsense were true.)” So sadly the 3,500 calorie formula is really not a reasonable estimate, let alone a very good one.

      Best wishes – Zoe

      • Thanks for the info. I am trying to lose weight and it helps me a lot.

      • The fact remains it IS a reasonable estimate.

        Your literally just complaining about something that doesn’t need complaining about.

        Anyone with half a brain knows every one is different and 3500 can’t physically be accurate for everyone. But at the same time you can’t start making things complicated by saying ‘you need to lose anything from 2500-4000 calories to lose a lb of fat’.

        People wouldn’t respond to this as it’s not simple enough.

        The generic 3500 rule just gets obese people (hopefully) aiming to lose 500kcal a day, which can’t be bad can it?

        One thing you haven’t mentioned which is completely relevant is an individuals BMR.

        My last point is that you continually state no one can provide an explanation where the 3500 formula came from, yet this was explained numerous times to you, as clearly explained by ASO.

        Maybe just to make you happy it should be changed to 3500 calorie deficit would lead to APPROXIMATELY 1 pound loss of BODYWEIGHT (fat, water, muscle, or carbohydrate). Would this satisfy you?

        You complain and nit pick yet you haven’t mentioned a suitable replacement?

        Your article will also singlehandedly make people eat that extra biscuit as you explained it as though the extra biscuit doesn’t actually matter – when it really does.

    • if it were actually true, an ACTUAL POUND OF FAT is 454 grams, thus at 9 calories average per gram, thats over 4,000 calories per pound of pure fat. think about it.

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  • I have two questions/comments that I am really hoping the author reads and responds to:

    1. First, since 87% of human adipose tissue is fat (we’ll just assume that’s a fact and forget about the variances as it doesn’t matter to my question), when you burn however many kcal we decide that is – say 3,555 – what happens to the other 13% that is not composed of lipids?

    I’ve been taught that once your body has created a fat cell it never goes away, that you can only make it smaller, but not ever get rid of it. So that means the non-fat parts would mostly stay right? An assumption that was not challenged in the article is the assumption that once you burn the 87% lipid content in a human adipose cell, the rest (13%) just disappears like magic! (Yes, we sweat some out, but we should be drinking that back in. Cutting water is no way to lose weight unless you are a wrestler the morning of a meet or something.) The other 13% is supposed to be water and lean tissue. A good program that is taking body fat% into account more important than the number on the scale should not be counting water loss and lean tissue loss as part of the success. It seems to me that we should use a higher number since we are trying to lose fat. All that other stuff that is next to, or inside of, the fat that isn’t fat shouldn’t matter, right? If 1 gram of fat is truly 9 kcal, that makes 4,082 kcal per pound of fat (not rounding up to 454 grams per pound). Why are we not just using this figure as we only care about losing fat? We aren’t trying to lose water or lean tissue.

    2. The issue of an adjustable metabolism is never addressed. I think this makes studies that simply take a kcal deficit over a period of time and measure the number of pounds lost inadequate for determining how many kcal it takes to actually lose a pound. Our bodies have amazing survival mechanisms and one of them is being able to adjust our BMR. When cutting kcal from our diet, our bodies think we might be entering a time of famine so they go into what I call Prius mode and try to get more mpg – or actually more hours per kcal – by slowing everything down. Wouldn’t it be great if our cars had adjustable horsepower? Kick it up to 400hp to zoom onto the freeway with lots of power but terrible gas mileage. Then dial it back to 90hp once you’re on the freeway and driving across the state so it doesn’t cost an arm and a leg. Our bodies can do that! Kcal deficits reduce BMR and an increase in lean mass increases BMR. I will attribute this as to why the ASO study showed weight loss at least 45 pounds less than it should have been over the 12 months. There are many studies we looked at in college showing two exercise groups, one cardio only and one weight lifting only, and comparing their body fat % decrease. Every time the weight lifting group wins even though they are burning less calories than the cardio group in their exercise routine. And if the study follows them longer, the weight lifting group also shows the weight loss maintained longer. Why? Adjustable BMR. Now of course, a combination is best. Slightly decreasing kcal intake with aerobic exercise, and anaerobic exercise.

    I guess my question is, why not talk about this aspect as well? It makes the official recommendations and dieticians look even worse when they recommend something like a 600 kcal deficit per week, but don’t warn anybody that if they do that they are slowing their metabolism and when they decide they’ve lost some weight initially and want to go back to their previous eating habits, they will blow up like a balloon.

    Thank you for your research. It is the most clear and thorough on the subject that I have found so far. I can’t stand the blanket statements people make and teach, like “there are 3500 kcal in a pound of fat” with no evidence. Thank you for helping to put them in their place!

    Nick P.
    Exercise Physiology, B.S.
    ACSM cPT

    • Hi Nick
      Answers in order :-)
      1) The 13% (whatever the precise amount is) is mostly water and some lean tissue. You’ve made me think of an interesting point – presumably the lean tissue (think more like protein than fat) will burn at a rate of c. 4 cals per gram (if any of this is right) and so some of the deficit will be lost breaking down protein (inevitably, even though this is not desired) rather than fat. Most will be water, however, and this is just lost as fat is lost. Take the extreme – a 200lb person c. 50% water has about 100lb water. If this person loses weight and becomes a 100lb person they don’t lose 100lb of fat and leave a puddle! Water is lost as a person gets smaller – there’s nothing we can do about this and there seems to be no way of protecting all lean tissue/muscle as we lose weight – just as we gain muscle as we gain weight – simply by carrying the extra weight around.

      We may only want to lose fat – but it doesn’t work that way.

      You’re right on the fat cells – they don’t reduce in number, but they can reduce in size. This is why childhood obesity is so critical – up to the age of c. 18 we can increase the number of fat cells – not just how much fat is in each cell. Hence – someone obese at 18 can have way more fat cells than a normal weight 18 year old. Even if the obese 18 year old manages to lose weight – they have more fat cells for life crying out to be fed. Dr Robert Lustig’s Fat Chance has some really nice discussions of the implications of this.

      2) Doesn’t seem to be a question – but a point with which I entirely agree. The Minnesota Starvation experiment was the definitive study of this. Then men lost weight to about 24 weeks and then, for some men, it didn’t matter what the calorie deficit was increased to, they just didn’t lose more weight. When you look at the systems of the body – some can totally be shut down to save energy. Periods stop in women relatively quickly with over enthusiastic dieting – the whole reproductive system, and all the energy this normally uses, is simply shut down. The body grow fine hair to keep the person warm – saving fuel needed for heating. Our survival mechanisms are extraordinary – anorexics would all die within months if this were not the case.

      You may enjoy this too – we also forget that some calories have jobs to do in the human body and carbs are pretty limited and yet we tell people to have 55% of their intake in the form of carbs! More lunacy

      I hope this helps!
      Best wishes – Zoe

    • Perhaps not much point on such an old reply to such an old posting but you’re mentioning the 13% non fat ‘excess’ and saying it doesn’t go away. This fits with something that crossed my mind which is that the general reduction of the figure to fit with this percentage fat idea doesn’t seem sensible, if the remaining ‘body’ of a fat cell is retained after conversion of the fat content then the conversion is 100%, there may be no extra lost if only the fat is consumed. Just a thought with no qualifications behind it beyond an engineer’s general scientific background.

  • Best part of this post is all the side links.
    The thrust of the main article is to question the conversion factor. Many respondents focus on the calorie input as a way of losing weight.
    My questions are:
    1. Why isn’t the mechanism for fat transfer written about?
    Many talk of “burning” calories, as if they disappear. I understand most “burning” chemical reactions to mean oxygen uptake and the result being heat produced and byproducts heavier for the addition of oxygen. The “heat” is potential energy converted to kinetic energy neither of which have “weight”. (And, please, don’t refer to Einstein’s work on mass energy transfer. We are not nuclear reactors). Fat or flesh doesn’t “fall” from you as you walk or lie about. Fecal matter leaves of course but this I believe to be indigestibles. Urine, sweat and breathing are not written about when dieting is the main topic. If the population better understood the transfer methods, which I don’t, perhaps they would not be as obsessed with calorie counting to reduce weight. Some of the external links in the reply posts suggest dieting can be detrimental to health.

    2. So given you have ‘extra’ weight, what are some very effective, non surgical, ways to remove it?
    This question implies that I do not want to calorie restrict to any great extent that may be harmful to my body. (Nitrogen deficiency, muscle loss instead of fat loss, dehydration, etc). I read that the chemical reactions relating to ‘fat’ require oxygen to deconstruct the fat to other byproducts ( I assume this means ‘burn’) . Then, other transfers take place to ultimately ‘dissolve’ the fats that are able to be transported out of the body in the form of urine, sweat, and the breathing mecahnism, such as the weighty carbon dioxide molecules.
    Which weight export mechanism is most expediant?

    Thanks for the article and to the many who posted external links.

    • Reg 1, any reason why the “standard mechanism” does not make sense? I mean glucose is basically C6H12O6 and over the entire energy cycle, it takes 6 O2 and converts into 6 H20 and CO2. (this is a cycle so apart from energy produced nothing changes).

      You should find the details here:

      The only remaining part would be the balance between blood glucose and stored fat. It appears that insulin and multiple other hormones play a role.

      From the above, I guess basically fat burning would take place as follows:
      1. ATP are energy carrying molecules. These are used up by cells (for instance while exercising).
      2. All cells have mitochondria that produce ATP from pyruvate. 2 Pyruvate molecules are generated from 1 glucose molecule (this ALSO produces 2 ATP).
      3. Glucose is basically blood sugar and decrease in its level results in body signals via low insulin / increase in other hormones. This results in liver releasing stored glucose to increase blood sugar.
      4. The hormonal signals ALSO result in triglycerides attached to VLDL (all over the body) to get broken up into fatty acids.
      5. The decrease in triglycerides results in more triglycerides (which are stored in adipose tissue) to get attached to VLDL and later move to other parts of the body.
      6. Meanwhile, the fatty acids are taken up by cells and via albumin by liver.
      7. The fatty acids taken up by liver are converted into DHAP and GA3P and converted into molecules that are a part of the glycolysis cycle. Ultimately these would result in ATP which may then be used to reconstitute glucose and store it in liver.

      To reply to part 2, I guess hormonal changes would result in fat being broken up and converted into energy carrying ATP. But if this ATP is not used up, more blood sugar entering your blood (from the food that you are eating) would accumulate; body would ultimately signal removal of this by esterification (i.e. creation of fat tissue) so we are back to square 1.

      My sense is that a physical calorie deficit is necessary to “burn” fat. Rather than physical exercise one could try hormones that promote metabolism (growth hormones, testosterone, adrenaline) but these are likely to have worse effects than calorie restriction.

    • Excellent,excellent comment. Richard Feynman (the genius physicist) would have applauded your critical thinking and looking at the problem completely anew.

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  • The 3500 calorie rule as an average DOES in fact work. What is missing from your article is the total calories obese people are eating I the first place. You do not become obese (in most situations) without an over abundance of calories in the first place.

    The answer to weight loss IS as simple as science. Eat less calories than your body uses and you will lose weight, eat more and gain.

    People need to know their base metabolic rate (BMR) to begin with. My body burns approx 1730 calories a day. That’s just the amount my body will naturally burn without moving a muscle. If I want to lose one pound and never burn any calories through exercise I need to cut 500 calories a day, meaning eat 1230 to lose one pound by the end of the week.

    An obese person’s body may have a BMR of 2500. If they begin eating 2000 a day, they too will lose one pound in seven days.

    The math may not be “perfect” and your body will go through times where it holds water/weight during your cycle or if you’ve consumed too much sodium, or had air travel. The trick is to stick with the calorie count daily and stay committed.

    The trainers on the Biggest Loser will tell you that the contestants lose their weight through calorie restriction mostly. 85% diet and 15% exercise.

    If a person eats 1200 – 2000 calories a day and nothing more, I can assure you they will lose weight. On top of your daily calorie counts, you may eat an unlimited supply of celery/cucumber. (Veggies with very limited calories)

    Lose It, is an app I’ve used for years to help with calorie counting. No one likes to count calories, but this app has almost anything you could find. Supermarket/restaurant items as well.

    Why get so wound up about the specific number and how you want dietician a to stop telling people this works. It does work!!!

    • Exactly. There is a lot of detail picking, but no mention to the fact that indeed following this formula (which is more like a guideline, and not exact science) you WILL lose weight. Thanks for leaving this important point in here. I wish your comment could bumped up to the top!

      • Her point (as I read it) is (a) that it’s held up as a very solid and specific number, when the “real” number could be 10-20% different, and (b) where’s the peer-reviewed science behind the number? The first point is a useful one to make, because if indeed it’s an “average” number, then you want it to really be an average number (a proper E() value). If you’re using it to advice 1 billion people, this matters. She’s commenting both with respect to individuals, but also about public policy. Second (b) point is one of intellectual rigor. Medicine in general is replete with these “facts” that, when you “click” on them, turn out not to be based on anything at all. Dieting in particular has been awash – such as when years ago it was a truism that cutting cholesterol in your diet would reduce it in your blood, then it turned out that there was no such direct metabolic connection, and later still it was pointed out that the initial truism wasn’t based on any science in the first place. So as a matter of principle, if a government health guideline can’t meticulously document its scientific basis, then that’s a problem.

    • The first thing wrong with your post is suggesting people need to eat under their BMR.
      And under the BMR is the caloric deficit that counts toward “weight” loss.

      So your BMR is 1730, if you did nothing more then sleep 8 hours and sit all day your daily expenditure would be approximately 2500 calories.
      So by dropping to 1230 you are in reality at a deficit of 1270 calories. Which should produce a weight loss of 2.5 pounds per week. But does that actually occur? See how the science isn’t simple at all.

      A caloric deficit can potentially lose weight. But physiologically your body will fight against it and shift your BMR as much as it needs to via physiological processes.

      The point is, the math is wrong. The science is not predictive, and therefore expectation and reality do not meet.

      Now obesity isn’t really the problem, because you can be obese with a 5% body fat.
      The problem is specifically fat, fat is a living organ in your body (currently classified as an endocrine organ). And when most organs are working improperly
      intervention is required sometimes more then the individual can provide.

      But! When someone doesn’t lose the expected mathematical predicted amount of weight the first thing people assume is – that they are lying about their dietary intake. They don’t have the willpower. They need to be more disciplined. No, no, no. That’s where the assumed simple science comes back in and fails anyone trying to lose weight that continually fails. Their bodies are dysfunctional.

      There are many ways a body can be dysfunctional to move a person’s BMR but also force uncontrollably binging.

      Back to the minnesota starvation experiment, those men were fed a ‘starvation’ diet of 1600 calories a day. They were not obese before the study started (unsure if any were overweight by today’s standards). These men would obsess about food, binge on junk foods when they were out and go through 60 things of gum to just manage their willpower. They could not stick to a diet, their bodies fought against it. (happens at all levels of body fat, but worse in obese possible due to leptin resistance theory)

      If this study is the factual basis for how weight loss truly occurs, then what it shows is humans are ruled by their hormones.

      And that was back in the day before rampant xenoestrogens, “food like processed products”, GMO (effect not completely known), meat animals fed: soy(more estrogen), corn, arsenic, and low dose antibiotics.

      So how do you lose fat? Lower cortisol, keep insulin low, balance sex hormones, increase body temperature, optimize thyroid(not tsh), increase hormone sensitive lipase, have adequate albumin, lower inflammation, nutrients optimised, build more muscle, and eat under daily energy expenditure (but above BMR to avoid nasty physiological revolt)

      Take everything you think you know about fat loss, and throw it out the window. It isn’t working long term.

  • Sorry, that should read “Banzai Otis” – need an edit button!

    I apologise that for that – that’s a mistake.

  • TBH Banzai, it sounded to me from your post that you were being as antagonistic as you assume I am being. Specifically thanking two people implies that all the other people posting are too stupid for you to bother talking to, particularly when you address everyone else as ‘folks’ in a sentence which sounds so patronising it made me feel sick. That’s how it read and that wasn’t constructive either. I wasn’t actually being antagonistic, I was trying to show that there was a bunch of other questions that this equation simply does not answer. And the point about the starvation issue is why did you bring up the point of a “picture of someone who starved to death” if that wasn’t the image you wanted to put into people’s minds? This is how it reads to an overweight person : “Picture of starvation = someone who lost weight = success!”
    You’re missing the point that many, many diets/medical advice are/is based on this theory – eat less than x and you will lose y in a healthy manner. If it isn’t true, it needs to be abolished. It needs to be chucked away and never brought up again. As long as any person can shout it at the obese, we will always get depressed obese who think that because they haven’t lost Y they are doing something wrong, not that the formula is wrong (or indeed that we shouldn’t have a formula at all).
    Why an issue with the length of the post? If we’re discussing complex issues (and I happen to think these are) it’s going to take a lot of discussion.
    To answer your points (in an opposite way, just how the post turned out):-
    You – Eating fewer calories than you need will result in weight loss*….I’m saying that caloric intake is a dominant factor determining body weight – can we agree on that?
    Me – Sorry, no. “Smash the fat” has already demolished this theory, and I too am showing it to be false with my high fat, low carb diet. I don’t even have to calculate my calorie intake, I just eat the correct food and my weight becomes less. This is not exactly radical stuff, most HF/LC sites will prove that a calorie is not a calorie is not a calorie. Do you agree that 300 calories of sugar are the same as 300 calories of chicken? We can agree that we need to eat.
    2. Putting fuel into a plane or a car is more exact than putting fuel into a biological organism. Can I ask whether you feel that putting half a tank of fuel into a car is a good idea to make sure that the car runs for longer than it would if you put in a full tank? If not, we can see that “Eat less, move more” doesn’t work, let alone provide proof that we can extrapolate some sort of equation from (and in effect you are asking people to move more in the sense that you are expecting people to do the same amount of ‘work” on less fuel).
    You : In fact, I specifically qualified my statement by saying that there are medical exceptions.
    Me : In which case, why are you arguing against the view point of someone who may have medical knowledge? My point is there are more ‘medical exceptions’ (in your terms) than you can happily cover by saying “There are some”.
    In closing, however, I would like to offer my apologies with regards to the assuming you would not be back – you are, and I appreciate it. I find it ironical that the two people you respond to have not been back – this is what gets me, you try to discuss stuff with people who just don’t reply.

    • Jessica,

      I don’t know what to say about your first few sentences. I thanked the two commenters because they put their fingers on a central point that I felt nobody else (that I saw) had. All that says about the other people is that I think they missed the point, which is exactly what my words said as well… I literally just got an email that went out to a big chunk of my organization, and it was addressed to ‘folks’. Maybe where you come from this isn’t a friendly term? I don’t know, but I’m just trying to discuss ideas here, not attack anyone. That was the source of my criticism about the length of your email – it was long without addressing anything I actually said.

      I brought up starvation to highlight the fact that, despite all of the complexity, at the end of the day there are some hard laws of the universe at work here. Some commenters (and maybe you?) seem to be challenging the basic physics of the whole deal and suggesting that you can somehow create an energy deficit and NOT eventually lose weight.

      Yes, I agree with the point you are making about different calories, although I would rephrase it to say that the body metabolizes different foods differently (since from an energy point of view all calories are the same). However, I don’t know of any reason that these differences would prevent weight loss or make reasonable approximations impossible.

      I don’t understand your points about fuel in a plane/car. I think MPG is a good example of a simple energy-use metric that does a good job of approximating a very complex system. That’s the only reason I brought it up. Of course using less fuel won’t make a car run longer. What does that have to do with ‘eat less, move more’? And what do either of them have to do with equations approximating energy loss?

      Re Medical: Again, I’m not saying anything about (or arguing against) your particular medical history. And I don’t want to argue my ‘some’ exceptions vs your ‘more’. I’m assuming that the huge majority of people (>90%) don’t have medical conditions which prevent healthy weight loss, but if you have some actual data refuting that I’d love to see it.

      Maybe we could shorten all this down a bit by focusing the point. I’m saying that food is the fundamental, dominant factor in body weight (but not the only). Given that first point, weight loss requires an energy deficit, and therefore healthy weight loss requires some kind of starting point for managing that deficit. This means medical professionals need to quantify it in some way, and the 3500 approach seems reasonable (as an approximate starting point, always taking into account extra-ordinary personal circumstances).

      It seems like you disagree, but I don’t understand your reasoning for doing so.
      What do you disagree with here? How has any of this been demolished or shown to be false?

    • It seems like you have had experiences with weight loss that are unlike those of the majority of people.
      Your opinion seems to be mainly based on your unsuccessful experiences with typical calorie deficits and a successful experience with a low carb, high fat diet. While it’s true that the impact of calories from certain foods, like carbs, can cause the body to react in a way that is negative for weight loss (insulin release) the foundamental understanding of all diets, including LC;HF, is calories out > calories in.

      LC;HF diets work on the premise that foods with high fat and moderate protein levels keep your body satisfied for longer at a lower calorie intake level. This is probably the reason that you are experiencing success despite not counting calories – you are naturally eating less and are seeing results. Of course there is a lot of research into ketosis ect but there is no scientific proof that you can lose weight while eating more calories than your body uses within the day, regardless of what your diet consists of.

      You seem to be quite worried about the prospect of people potentially starving themselves, despite that fact that cutting out 500 calories a day is in no way life threatening for someone eating at their maintenance level, especially if they have weight to lose. Considering that the majority of overweight people are eating at above this level there are, in most cases, no health risks involved in cutting those calories out of an inflated diet.

      Since you seem to be advocating ignoring calories completely could you recommend a sustainable alternative, keeping in mind that obesity is steadily rising?

      The current policy advocates reducing your calorie intake to avoid overeating, and also advises about heathier choices that make this possible without sacrificing much food in absolute terms (200gm steak vs 100gm of chicken nuggets). There are also many tools online that allow you to find out your BMR and similar stats, avoiding the under eating that you seem so worried about.

      What exactly is wrong with the current method?

  • There is no “formula” necessary in determining how much energy is contained in a pound of fat. A pound of fat can simply be burned in a device known as a bomb calorimeter to determine how much energy it actually contains. This is the same type of device used to determine the calories listed on the back of all the packaged products you buy at the grocery store, etcetera.

    While I’m sure the calorific value of body fat varies from person to person, or even from one area of the body to another, I’m also quite sure that 3500 is probably a pretty good average approximation. And while burning an excess of 3500 calories may not result in the loss of a pound of fat in the short term, it will in the long term.

    Eric J
    B.Sc. Chemistry

    • Oh phew! Thank you so much! I was dying to post the same. Using words such as ‘nonsense’ in the blog is ridiculous in this instance. The writer is being far too picky. If one were a top athlete then fine, get down to the nitty gritty and fine tune a diet but most people, particularly obese people with health problems who need to lose weight, will most certainly do so using the original equation and wouldn’t dream of reading all this pedantic fluff.

      • This formula is used to beat obese people over the head with when they fail to lose the correct amount of weight. The formula is wrong, so why is that so? Why should obese people be judged on how much weight they lose according to a formula which is incorrect? Why should obese people be accused of “eating more than they are telling” by their own doctors when it is not them, it is this flawed equation? Why should obese people be shoved into some sub human category by the smug slim who tell them to follow this formula – which doesn’t work? Suddenly, this “pedantic fluff” becomes a point of such importance to those of us who cannot lose weight in the way that we are scornfully told. I wonder if you understand that a choice between losing weight and losing one’s life becomes a decision one thinks about constantly, because there are people who will assume that this formula will always work, and if it doesn’t, it’s the dieter that is “not doing it right”, not the formula.

        Tell you what; think about these questions for a moment.

        Will an obese person lose more or less weight than predicted by the equation at the start of their diet?

        If your doctor told you that according to his formulas, you would lose 5% of your hair and your actually lost 95% of your hair, would you feel that this was your fault, or the fault of the formula? Would you be concerned or comfort yourself with the thought that at least other people wouldn’t lose as much hair as yourself?

        Does a cheetah, when it’s caught an impala, consider the amount of calories it should be consuming so that it does not put on weight?

        What is the difference between an anorexic on 400 calories a day and an obese person on 400 calories a day?

      • Thank you Donna and Eric! The majority of this post and comments seem to miss the point of the rule: It’s a heuristic, folks! It’s not a law of nature (and definitely not a ‘theory’ in the scientific sense). It’s like saying your car gets 30 mpg, so if you go 60 mi you should burn about 2 gal. Yes, fuel consumption is actually a factor of a zillion variables other than distance. Yes, there is all sorts of fancy physics going on, and I could invoke Newton and talk at length about the inaccuracy of applying a linear measure to a non-linear phenomenon (“… but air resistance increases with the cube of velocity! mpg must be baloney!”). I could argue from the margins ad nauseum about how my car gets 1,000s of mpg when I roll it down a hill in neutral. I could even get on my soapbox and demand that we banish the mpg metric until a perfect formula arrives that correctly estimates every milliliter of fuel use, in every car, in every instance.

        None of this matters for the problem at hand. For most people, most of the time, 2 gallons will get you about 60 mi. Unless you are designing a multi-stage rocket, you probably don’t need much more precision. And for most people, most of the time, eating less results in weight loss. We can squabble about how representative the 3500 number is (and I would defer to empirical work on that issue), but all of this other detail about thermodynamics and ‘proofs’ and what-not is seriously overkill.

        With some rare medical exceptions, eat less than you need and you’ll lose weight. Just ask anyone who has ever seen a picture of someone who starved to death.

        • No, I’m afraid you’re missing the point. Why is “starving yourself” a good way to lose weight? Why do you feel that starving yourself until you are a certain weight (if you get there before health issues kick in) is a solution, when as soon as you reach your target weight, you either have to keep starving yourself, or look forward to putting on weight. The phrase “starve yourself to death” seems to be fairly indicative of this being a bad thing to do, and yet you still advocate it? Very strange. Do you understand that it is possible for a fat person to die from starvation?

          There are some rare exceptions to “Don’t starve yourself”. For diabetics, starvation can sometimes kick start the body. For me, even low carbing made no difference to my Blood glucose levels until I stopped eating for almost a day. When I began again, I ate only fat and protein. Suddenly, low carbing worked. The 600 calorie diet has had some success with diabetics – I would like to see more research into this, because there does seem to be some evidence that it will work, if there is a sensible follow up to it.

          However, we are constantly hit over the head with this “Eat less than X and your lose y” equation – do you not understand that this is the case? Have you never heard of this equation before? I certainly never want to hear it again. When medical advice is based on flawed numbers, people should be worried. If I had to take arsenic and a doctor told me they had no idea how much I should take, just to take some until it had an effect, I personally would not take any. When did medicine become based on guess work? When you say, “Eat less than you need” can you tell me how to work out exactly how much less I need to eat? How do I calculate my breakfast when I have no idea what I may be doing that day? How many calories – exactly – did I burn yesterday? How many in my sleep? You can’t tell me? So I should just “eat less”. How fast should my weight loss be? Should I eat less so that I pass out and go into a diabetic coma? Should I eat less to the point I start to develop organ failure? How do you know what my calorie intake should be? If I eat very little and I am then forced to be very physical, how much weight will I gain (and I will gain weight)?

          I presume, that from where you are sitting, you know my exact medical history, and how much I do every day, how much I will do over the next few weeks and how much weight I can look forward to losing? How about my colleagues?

          I will check back to see if you have posted any answers but I get the feeling that you don’t really want to understand, you just want to be one of the “Eat less and move more” brigade.

          • Jessica,

            Will you take this down a notch or two please?

            First of all, you are arguing against a bunch of strawmen. I never said that starving was a good way to lose weight, or advocated starving to death. I never claimed exact medical knowledge about anyone. In fact, I specifically qualified my statement by saying that there are medical exceptions.

            Second of all, you didn’t address either of my two points. You just said “no”, and then told me I was missing the point (without ever stating what that point was exactly).

            Finally, you capped it all off with insulting my character by suggesting I’m some sort of closed-minded ideologue.

            A flat denial, followed by a list of strawmen and ad hominems longer than my original comment, isn’t exactly constructive.

            I have two points:
            1. The 3500 rule is a rule of thumb. It is an approximation, an average, and so BY DEFINITION is not exact. So complaining that it isn’t exact, or that it should be abolished unless it can be proven exact, is unreasonable. If you take that stance, you would also end up throwing out the equations that tell an airline how much fuel to put in a plane, or tell a breathalyzer whether someone is drunk or not. Both of these are approximations, but the point is that they are good enough for everyday use. Of course 3500 kCal/lb isn’t exact – no average is. This was the point of my mpg example. With averages and heuristics, the question is never whether they are exact or not (because they aren’t, by definition). The question is always about how representative they are and when they are most appropriate to use. And 3500 kCal/lb seems to be representative and useful for most people, most of the time. If you think another value or metric would work better, then THAT is a conversation worth having. Complaining, because you found out that an approximation turned out to be approximate, isn’t.

            2. Eating fewer calories than you need will result in weight loss*. If you are gaining too much weight, you are eating too many*. If you aren’t losing weight, and you want to, then you need to eat fewer*. If you aren’t changing weight, then you are eating exactly what your body needs to maintain that weight*. I only brought this up because some of the comments below (and even yours) seem to call this basic principle into question. I’m saying that caloric intake is a dominant factor determining body weight – can we agree on that?

            If you want to respond to either of those points, I’m happy to try and understand, but please don’t bash me over the head again with a bunch of stuff I never said.

            *Obviously, all of these claims are for most people, most of the time. Outliers with some sort of extreme medical issue will be different – just like a 30 mpg rating is useless if the particular vehicle in question has a faulty fuel pump.

        • There is no such thing as a “law” in science. They are our guessed models ,fallible and provisional. Manuel Uribe would pass away of starvation before he lost significant fat on a deserted island.

    • I don’t think the bomb calorimeter approach is used for foods directly. If it was used, 100g carrots would have pretty much the same calorific value as 100g bread. The real reason why carrot has low calories is because it has cellulose (fiber) which the human body cannot digest. I am guessing that the way calorie listing is done is by isolating sugar, fat and protein from the food and then using standard values for those.

      Also, my sense is that the calorific value for food once it is digested and absorbed by the body is pretty much the same across people. The pathways for converting fat into ATP and using ATP in muscles are pretty much the same for all animal. The real problem is that “calories” is defined for the food that you eat and not all will be absorbed by the body (Starch or carbs are easily digested but proteins and fats take hours; if for some reason the food does not get all time in the stomach / intestines these are lost).

      The other issue is that consuming 100 calories less (or even exercising 100 calories worth more) does NOT result in a 100 calorie deficit. This is because our metabolism changes typically towards an equilibrium – when less calories are available the body slows down and tries to conserve them. The further issues is that this feedback mechanism varies person to person (and also mood to mood).

  • So, let me get this straight. You say the “3500 kilocalories per pound of fat”-number is wrong, and then you do some maths which shows the number is a decent approximation?
    … Ooook.

    • Yup and then she shows some studies which shows that it is off by a factor of 10. Guess are bodies are not good at math :)

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  • hi zoe, before i start love your dog walking blog i do 20 miles approx with the dogs each week, it keeps me sane!!
    anyway, 3 years ago i was 14 st now i am 10st and hve maintained that for 1 year so far. i counted calories mainly because i could do it for free, no books, no monthly payment to weight watchers or whoever. it worked. but looking back i am inclned to think it was a combination of things rther than purely sticking to numbers religiously.
    changing my diet from lots of chocolate to healthy foods not just low fat but real food, getting more active and having the visual affirmation of weighing foods and keeping calorie diary. as i say i never stuck to numbers religiously but i can’t ignore it worked for me
    i no longer count calories or weigh food, i do use a smaller plate which has always helped.
    i do believe people need something tangible to hold to and calories worked it for me but i’m not daft enough to think they were the ultimate reason for success.
    people need educating, it should start in schools, the food industry needs exploding and starting again from scratch! the amount of sugar and excuse language crap that goes in food is unacceptable
    also you can feed a family on good food as cheaply as you can on junk food, we are a low income family and i feed all 4 of us on healthy food as little processed as possible, it can be done
    i fear your mission is going to be a long one but every voice helps :-)

  • The issue of thermodynamics in general is pretty screwed up in the media, because the media and millions of regular folks simply don’t understand the subject.

    Millions of people understand a tidbit or two, and confuse this partial knowledge with expertise.

    Thermodynamics involves just a few laws which are used to make statements about what is potentially possible and what is forbidden.

    It is well known that it is energetically possible for diamond to spontaneously change into the lower energy form called graphite. It is an “allowed” process, not a “forbidden” process.

    All “”allowed” (energetically favorable) processes do not indeed happen spontaneously. Diamonds, by millions of observations, do not decompose to graphite at any readily observed rate.

    The Rate of Reaction, is not a concept of classical thermodynamics at all. Most commonly it is covered under the topic of Kinetics, usually called Chemical Kinetics.

    You can look at the tables of contents and indices of dozens of books on thermodynamics and there is virtually no mention of chemical kinetics. Classical thermodynamics simply does not predict the rates of chemical reactions or phase changes. Kinetics addresses these concepts.

    There are, commonly accepted, four laws of thermodynamics (Zero, First, Second and Third Laws). If somebody doesn’t know all four laws of thermodynamics, I don’t bother to discuss anything they say about “thermodynamics”. If someone don’t know why there is a zeroth law, they are missing something of basic science.

    Because of the basic ignorance of the subject, there is great misrepresentation of the subject in dietary literature.

    The “idea” of 3500 Calories of food deficit resulting in one pound of weight loss is just one glaring example.

    I have never met a “Nutritionist” with or without degrees who knows the four laws of thermodynamics. Of course none of them actually know what is properly predicted (or not predicted) by classical thermodynamics.

    • Hopefully I’m the nutritionist exception knowing the zeroth to the third laws and how and why they came about:-) Probably why I totally agree that this whole subject is a great example of a little info is a dangerous thing. I remember the first time a dietician told me that the calorie theory was true because you can’t change the laws of the universe. Battle of wits, unarmed person and all that!

      • Thermodynamics uses the term “spontaneous” in a different context than ordinary language. It does not mean rapidly or immediately. Spontaneous applause, for example, is usually immediate following some event. According to Professor Peter Atkins, in the book “Four Laws that Drive the Universe”, states the following (page 54).

        ” The word ‘spontaneous’ is another of those common words that has been captured by science and dressed in a more precise meaning. In themodynamics, spontaneous means not needing to be driven by doing work of some kind. Broadly speaking, ‘spontaneous’ is a synonym of ‘natural’. Unlike everyday language, spontaneous in thermodynamics has no connotation of speed: it does not mean fast. Spontaneous in thermodynamics refers to the tendency for a change to occur [not necessarily its actualization]……. Thermodynamics is silent on rates. ”

        The digestion of lactose (milk sugar) for most people is not only spontaneous, but it is actualized at a useful rate (by observation). Hidden within the reaction pathway for lactose digestion is the key activation of a chemical stage by the enzyme (organic catalyst) lactase. Without this enzyme (catalyst) lactose will not digest and the calories within this lactase will not be converted into energy by the body lacking this enzyme.

        Many Asians and American Indians, among others, lack this enzyme.

        Therefore, at least for lactose, a calorie is not a calorie. Whether or not the calories in ingested lactose are converted into “energy” depends on the presence of the catalyst (enzyme) lactase.

        Humans are not all Model T Fords, some are of other makes and models.

        The pseudo-theory that “a calorie is a calorie” expresses ignorance of the human biochemistry to which it is applied.

        • I think there is a difference between the way nutritionists and physicists define a calorie. There is the whole calorie is a kilo calorie issue but there is also more. For instance, why would vegetables, say carrot, have low calories? It is mostly cellulose and cellulose burns quite well releasing a good amount of energy. But still cellulose has zero calories and carrots have very few.

          Basically when a nutritionist says that xyz has 10 calories, he means (probably without knowing it) that xyz has chemicals that when absorbed by the average human would result in an equivalent number of ATPs as an amount of pure sugar that gives 10 kcal in a calorimeter.

          Also, yes a calorie is not a calorie but then even in thermodynamics, a joule is not a joule. I mean that a joule in heat at 273K would be pretty worthless while the same at 1000K would be very useful while joule of electricity would be the best. All sciences works with models and models gloss over details while giving conclusions that are useful. Let us not bash up nutritionist just because their science is inaccurate; instead let us bash them up up because they have been lazy in not giving us accurate answers (or even in telling us what the inaccuracy is).

    • Wrong. The universe does not have to obey our laws.our laws ade NOT rules imposed upon nature, you misinformed person,Nothing is immutable or ubquestionable in science. It dows not conform to human Invented mandates. Nothing is forbidden. Just supported thus far….

  • I must say, there seems to be a lot of missed points here.

    First, the 3500 kcal/lb is ludicrous on any number of levels, and many good points have already been made, save for the most obvious one – just because X Calories of food (notwithstanding the fact that not all Calories are equal) are consumed, that does NOT at all mean that the body has to do something with that stored energy.

    Second, thermodynamics is NOT simply about movement of heat energy. It is the study of energy transfer in chemical and physical reactions. That includes reactions in which heat or motion energy might be converted to potential energy in chemical bonds. Digestion, storage, and use of the stored energy in food or from fat involves chemical reactions and the manipulation of chemical bonds to release and store energy.

    Third, and related to the first, it’s not simply a matter of stored energy in = energy the body has to do something with because different food types give the body different biological cues – they don’t just go into an unchanging furnace. Almost all foods can trigger biological adjustments throughout digestion (e.g. sugars and simple carbs upscaling insulin production from the moment they’re sensed in the mouth (or even before if the subject is anticipating) or gut, or fats slowing down digestion to ensure enough time for chemical processes to work correctly, or fats causing the release of specific digestion-aiding chemicals, etc). These triggers can cause the body to behave in very different ways regarding fat storage, metabolism slowing/speeding, osmotic balance, etc, etc.

    IMHO, the real problem is not whether or not thermodynamics has to do with weight, but whether 1) all incoming Calorie-equivalents of food are equal with regard to fat storage, 2) all Calories stored in bodyfat are equal no matter the circumstance of use, and 3) the rather loose interrelation between Calories and weight (of fat, muscle, or whatever) is EVER useful in the first place.

    • You can write a lot of “possible reactions” that satisfy the first law of thermodynamics [energy], but that doesn’t mean that the “possible reactiion” you wrote WILL ACTUALLY HAPPEN.

      Among other things, the “possible reaction” must also satisfy the second law of thermodymanics [entropy].

      Even if both the first and second laws of thermodynamics are satisfied, that doesn’t mean that the “possible reaction” actually occurs at a practical rate. The classical thermodynamics subject is devoid of any concept of kinetics.

      For example, the traditional example of the thermodynamically allowed spontaneous decomposition of diamond to graphite (at room temperature and pressure) does not proceed at a readily seen rate. In addition, most biochemical reactions are thermodynamically allowed but will not actually occur without the appropriate enzymes being present to catalyze the kinetics. Enzymes can speed up biochemical reactions by well over a million times.

      Folks who lack the lactase enzyme cannot digest lactose and generally avoid drinking milk as a result.

      So, just because someone can write a reaction that says that a pound of fat is calorically equal (upon laboratory bomb calorimeter testins) to 3500 calories doesn’t mean that this results in a practical sense the loss of one pound of fat for each 3500 additional calories dissipated or expended somewhere or everywhere in a human body.

      This thinking shows that the writer knows some pieces of classical thermodynamics – yes. but does not actually represent proper application of the application of thermodynamics.

      However, a claim that 3500 additional calories of energy dissipation or utilization in the body results in 2 pounds of fat loss appears to be a violation of the first law of conservation of energy. That is that this 2 lb. for 3500 calories proposal is apparently a violation of the conservation of energy ( the same as the first law of thermodynamics).

      • Paul Lutus would educate you. There arexNO LAWS in science. Thermodynamics is THEORY.

  • appreciate this blog page Zoe, it’s got me thinking.

    I agree with the 3,500 calories being too wide an estimate to be relied on but I still think we can play with the numbers and see what happens on the scales where it matters. I try to lose weight by leaving myself a calorie deficit of 250 which in theory means I should lose 1/2 a week – I don’t. if after a few months I have lost more than I wanted I increase my calorie intake and so on until I lose a staedy 1/2 a week, I get to my goal weight then try to maintain it. The key is to weigh myself every week – playing with the numbers is harmless enough if I keep one eye on the scales.

    What I’m trying to say is that I agree, calorie counting is not scientific but weighing yourself every week is – if i’m playing with the numbers (3,500 calories = 1lb per week, 250 daily deficit etc) and I gradually lose weight where’s the harm?

    Surely a systematic approach (even if flawed scientifically) is better than just eating healthy and not counting any of the calories – surely you would just put weight on?

    Thanks Zoe.


    • Hi Andy – I wrote a 134,000 word book mostly about this!

      Interestingly – this is what Keys did in the Minnesota Starvation Experiment. He did not adhere to or mention the 3,500 theory at any stage but tried instead to develop his own formula and he then resorted to your kind of trial and error. He would weigh the men each week and adjust their calorie intake down further if they weren’t losing as he wanted them to. The trouble is – at about the 6 month mark when calorie deficits seem to reverse for most people – he could no longer induce further weight loss for many of the men and some even started regaining at around 1,000 cals a day or lower and they were trying to steal food with hunger!

      I never subscribe to eating less – only ever eating better. I’ve written so much about what happens when people try to eat less and losing weight is not the only or even most likely outcome.

      The videos on here may help!
      Best wishes – Zoe

  • Hi Zoe the information you have presented is really fascinating. I myself have been on diets to lose weight and they all worked using the calories in calories out formula. For example I calculated my BMR then x using the Harris Benedict equation found myself to be needing 2700 calories to maintain weight. So i consumed 2000 calories a day and found myself to be losing about .7 pound a week exactly as expected. Later I did the reverse and the expected outcome was achieved, but with a 500 surplus. The doctor doing my dexa scan gave me the calories in and out formuala advice when going on a weight loss plan aswell. But if there is no literature so conclusively support the argument I don’t see how people are giving this advice. I myself have given people this advice as thought it was universally accepted, and becuase it worked for me! If there is no literature or formula to support weight loss what advice can we give dieters?

    • Hi Shannon – the advice I give on the calorie formula is don’t believe it – it simply does not hold. Never has; never will. I bet it only ‘worked’ approximately for you and in the very short term. Do it for a year and see if you lose 104lb in fat alone – more in water and lean tissue. There is no formula. I know that people want a formula – do X and this will happen – but there isn’t one and anyone who suggests otherwise is lying and being cruel with people’s hopes.

      The advice I give on weight loss is 1) eat real food 2) three times a day – stop grazing! and 3) – if (1) and (2) haven’t got you to your natural weight then manage carb intake carefully.

      Good use of the Harris Benedict equation though – not many people take care to know the deficit needed :-)
      Best wishes – Zoe

      • Ill never lose 100lbs of fat because im 76kgs. All im saying is I monitored my calorie intake and like predicted the the amount of weight(not fat)came off. I lost 6kgs of fat and 1kg of muscle!(dexa scan results)It wasn’t approximate it was pretty much exact(within .25kgs) All i’m trying to say is there is some merit to the theory, maybe not in extreme cases of obesity but for people in an acceptable body fat% ranges(I have no evidence to prove that statement it is just anecdotal), however the most important part is knowing how your body is responding to the food your consuming, not what your consuming, hence most people don’t understand how to apply to the calories in and out theory. Therefore it is so hard to prove.

  • My son eats ten times what we eat and he is still a string bean. This ‘theory’ of energy in and energy out does not work. He sits at under normal weight on the BMI and is six foot two inches tall. He eats at least five litres of ice-cream every two days, plus, for every meal he eats two, the second usually an hour after the first. Two breakfasts, two lunch two dinner, plus stuffs himself with chips (he is starving all the time), he will eat a whole chicken not just one piece. I’ve been in touch with dieticians regarding his weight and their advice is to bulk up his food with things like sustagen powder, add oil and fat to meals (more than he is eating), and he is STILL skinny. When I looked at what was in Sustagen, I wondered why dousing a boy in soy powder could be good. And he does NO exercise at all. He has always been like this, underweight. a theory is an idea. When it is proven then it becomes a fact. It seems the theory is being ‘sold’ like it is FACT. If it was fact, my son should be getting fatter as he has stopped growing but still eats enough for five people, every day.

    • NO.

      In the sciences, a theory is NOT “just an idea.” I am sooooooooooooo tired of this general misunderstanding of the word “theory”!

      In the broadest terms, a theory is a solid body of tested principles that explains how something works. It is NOT just some random idea that somebody pulled out of their hat.

      A HYPOTHESIS is more in line with “an idea,” because it hasn’t been tested yet. Once a hypothesis is sufficiently tested using the scientific method, then it can be considered a theory.

      So if the “calorie theory” does not actually have such a solid basis, then maybe it should be referred to as a “theory” at all!

      • Our “laws” are OUR BEST GUESSES. They ade approximations only. Our guesses and extrapolations into the unknown . Very fallible. They just went through the sieve some. A theory is just a theoryBUT it is well supported. I understand your point that common usage means only a hunch.

      • STOP overstating theories and getting your information from misinformed incompetent science popularizers liek Sagan and Tyson.

        Theories are only very fallible PICTURES MODELS BEST GUESSES. That is all laws are as well. THEY ARE best guesses that have been put through the sieve. Today we KNOW General Relaticvty is WRONG Aas Sean Carroll notes. i is omnly a gross approximation NOT really the case despite having “lots of support”. All experiments are inaccurate as feynman said. New info is gained WE THINK QM is correct so G,R IS NOT. This is CARROLL SAYING THIS

        FAR DEEPER PRINCIPLES underpin G.R . It may not stop with String Theory either. Einstein felt we will NEVER see the body of the lion ever,nor the face , just the tail


        A bad guess pulled out the butt – a BAD guess is not what a theory is. Som bum who just blurts out a bad guess is not what a theory is. But it starts out as a wild guess sometimes . AND REMAINS just a BEST GUESS/ We do not have access to Nature as it really is. WEe do not evben knwo the orign of the universe as WEINBERG NOTES. Sagan was a jerk who was DENIED TENTURE at Harvard fro being so pompous, overstaing science and ghis own work, promoting hiosmelf and preying ont he public. His work was nothing special…. According to colleagues very uninspirign, unoriginal and derivative…

        . He spewed misinformation.


  • Splendid piece or inquiry into commonly touted official ‘science’!

    But sorry, the whole calorie thing is simplistic nonsense, not even worth a moment’s consideration.

    Calorific values are arrived at by nothing more complicated than burning food (or fat/flesh/bone etc), and measuring the heat produced.

    So there is this idea that putting on bodyweight depends solely on calories consumed, balanced against energy expended (E=mc²). Utter balderdash

    Consider at first thought: petroleum, coal, wood are generally known as splendid sources of heat when burnt.

    So – according to the patently lunatic calorie theory – if you are under-weight and each day eat just a medium-rare lump of coal with wood chips all washed down with a nice glass of kerosene (maybe include the paper plate), you should put on weight in no time.

    Perhaps I should conduct an RCT to be sure, but I’ll hazard a guess that the hypothesis is not going to fly. What in my young day we used to call “reductio ad absurdum”.

    The theory is palpable nonsense. Wake up now, you know it’s nonsense. You would have to be severely nutritionally deprived to even to begin to consider it has any merit whatsoever.

    Which is even before glancing at the role of, say, water.

    The point is that the calorie theory skips the essential point: that the quality and composition of foodstuffs is of prime importance, not its potential for generating heat (except perhaps as spurious argument).

  • Hi Zoe,
    The whole problem is that certain sectors of the medical fraternity view human activity using a “furnace model” – i.e. energy in vs energy out. If there is a imbalance internally it must be turned into something in the body. A pound of fat internally has a calorific value of about 3500 cal, so then if there is a deficit of this amount the body needs to keep the energy equation constant so it will somehow burn a pound of fat or deposit it.
    The energy content of foods are rated according to how much heat they will give off when burnt.
    This completely ignores the fact that after eating certain foods (fats) a person will feel satiated and not want to eat anymore for a while, whereas other foods seem to induce a permanent feeding frenzy because they induce a cycling full/empty feeling (carbs).

  • Sorry if anyone else has already pointed this out, but the formula also fails in the other direction: people on hypercaloric/force-feeding diets and studies rarely gain one pound for every “extra” 3500 calories they eat. In fact, if not coming from a history of restricted eating, they often gain at a rate of less than half of what the formula says they “should” be. (For example: an account of a girl eating 5000 calories per day gaining at the rate of 50 pounds every six months, or 8 pounds per month, despite the fact that given her weight and daily energy expenditure, the formula would have her be gaining 18 pounds per month!)

    • Good point Spencer! The Vermont Prison Experiment and the Horizon prog – why are thin people not fat? And every documentary about morbidly obese people where we’re told they eat 20,000 cals a day – bedridden – and they’re not gaining 4-5lb every day!

      • The only formula anyone needs to know is: energy in – energy out = change in weight. There is no need to quantify how many calories it takes to burn a 1lb of fat.

        The reason a huge person does not gain 4lbs a day eating 20,000cals is as follows:
        The amount of calories a person burns in a day is dependent on their weight and how many calories(energy) is required to “maintain” that weight. I weigh 180 there for my ‘caloric maintenance’ amount is X. If I eat X every day I do not gain or lose weight. If another person weighs 500, their maintenance calorie amount is XXX. Therefor they can eat more than me(XXX) and not gain any weight. The person will only gain or lose weight when they over or under consume calories. Your “healthy daily value” of calories depends on how much you weigh when you’re healthy.

        • Hi Nick – you’re making the mistake of relating energy to weight. Thermodynamics is about energy (the movement of heat to be precise). It says nothing about weight.
          Best wishes – Zoe

        • Hi Nick–your assumptions re: the mechanics of weight gain (as Zoe pointed out below), aside, those differences in metabolic rate were accounted for in the calculations.

          The girl in question (I’d rather not link to the article as I know the circumstances of her weight gain will just cause unnecessary controversy) currently weighs 230 pounds and eats, on average, 5000 calories/day. Given her weight, and assuming she sleeps 8 hours a night and is sedentary the rest of the day, a formulaic metabolic calculator says she requires 3,111 cals/day to maintain her weight. This would mean she is eating approximately 1,900 “extra” cals/day, or 360,000 extra calories over the course of six months.

          According to the same formula which claims 3500 extra calories = 1 pound of fat gained, she should be gaining at a rate of about 100 pounds every six months, or about 17 pounds per month. However, she’s actually only gaining at a rate of 50 pounds every six months, or 8 pounds per month.

          Zoe: thanks for mentioning those studies! There are many others that corroborate your findings as well; this is just the first I could think of off the top of my head but it’s neat (old, but that shouldn’t mean it’s discounted–the sample size was several thousand people):

          “Blood sugar concentrations and indices of glucose tolerance correlated positively with the degree of adiposity but tended to be negatively correlated with total food energy intake and its component nutrients (total carbohydrate, sucrose, and fat). This inverse trend was largely accounted for by highly significant inverse correlations between food energy intake and adiposity, a relation found in both sexes and in all three population samples and which extended across the whole range of nutrient intake and BMI.”

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  • Many Thanks Zoe :-)

    Couple of thoughts which have been touched on already:

    A major issue with CICO/ELMM is the focus on “weight”, whereas it seems to me that most who “diet” are more interested in shedding excess fat mass and probably gaining lean muscle mass along the way… neither of which are best served by measurement of “weight” alone.

    The second one for me is this idea of creating a calorie “deficit”… I think this belies the fact that what we put in our mouths and how much time we spend on an elliptical trainer, are only part of the overall picture. There is so much more going on metabolically, over which we have much less (if any) concious control.

    I find it funny to think of dietiacains who decry saturated animal fat as a killer while advocating calorie-restriction. Don’t they realise that their presciption is causing an high-fat “diet” for their patients… sarurated animal fat as in, human fat which is almost identical to lard?!?

    No, if you consider that E-In and E-Out have to include the body’s own stores, then I submit that there NEVER is a deficit, unless we are dead or dying.

    CICO is wrong-thinking and a far too simplstic approach to the subtle adaptations which have shaped our metabolism over millions of years. Litte surprise then that CICO doesn’t work.

  • Well, now you know Its because the theory of that formula has never been proven in any study. But this avoids the more important question which is, “what is a calorie, anyways?”

    A calorie is a measurement of ‘potential energy’ which is not the same thing as absorbable energy.

    Even the way calories are measured have flaws in the way we are using a bomb calorimeter. For one, there was never a consensus regarding the starting temperature of the water in the calorimeter, nor was the atmospheric pressure defined. Second, the calorimeter is measuring the potential energy In a closed system. We are not taking in the energy from food in a closed system. We are not a bomb calorimeter. And in fact this process, ignores laws in thermodynamics.

    Now many will state, that weight loss is all about the laws in thermodynamics. Because ‘Energy is neither created nor destroyed, it only changes forms.’ But that is a law in energy conservation, which is the foundation for the laws in thermodynamics, but not a law in thermodynamics itself which deals with energy transfer from one closed system to another. Of course, one of the laws of thermodynamics states that in order for energy to be transferred from one closed system to another closed system, energy must be lost in the process. This concept has profound impact on our understanding of nutritional intake.

    What’s more interesting to me than all of that, is why do we only use one law in physics to rationalize weight loss? There are many laws in physics that are blatantly being ignored.

    I’m speaking to a group of doctors regarding this very topic in about 14 days. I hope it goes well, and we can stop it with this calorie nonsense. (Fingers crossed)

    • Hi Darin – what a great comment. Please can you post your talk somewhere? We’re working on a follow up blog on exactly this kind of stuff – the errors that people make when they try to apply ‘the laws of the universe’ to dieting. We hadn’t gone into the what is a calorie/calorimeter errors – we go into the misapplication of law 1 (conservation), ignoring law 2 (entropy), non reversible processes and – our most important one – the laws are about energy, heat and movement – not weight. That’s where humans went wrong!
      Many thanks for this
      Best wishes – Zoe

    • Correct. However, the “laws of thermodynamics” are not laws.It is ALL theory. There are no laws. in science, as Paul Lutus stresses.

    • None of you people on here understand anything about physics. Energy is a number, a human invented “mathematical fiction” we find useful for nice neat tidy bookkeeping and calulations convenience. IT HAS NO EXISTENCE WHATSOEVER IN ITSSELF PLEASE READ THAT AGAIN

      STOP treating energy as stuff. No. It is NOT stuff at all! It is neither invisible, nor intangible nor nebulous. Understand this: Energy is A NUMBER ONLY!!!!! AND NO, energy is NOT like radiation or radio waves etc. Radiop waves while mnot matter nor visible to humasn IS STUFF and CAN ACT Such is NOT- NOT the case for a NUMBER we call “energy”. Energy does not have to come from somewhere BECAUSE IT IS NOT STUFF! Physicist Peter M brown at the Naked Scientists Forum went into ddetail about this!!!!Please READ it!!!!!

      Calories, joules, inverse fermions, ergs, etc. – ALL exactly the same- they are ALL HUMAN INVENTIONS , NOTHING MORE FICTIONAL, they do NOT exist. “Calories” , “joules” are toally made up and do NOT exist in Nature. We could do away with calories this very moment. Understand this: Calories, inverse fermions etc. CANNOT ACT on human cells is ANY way! Enertgy CANNOT act in any way on cells. Read that AGAIN. it is from TOP TIER phsicists Energy CANNOT AND DOES NOT AXCT on huamn bodies. Energy does NOT make things move or go either . Energy is NUMBER huymasn assign to objects. The amount depends upon the observer, too. Energy

      You CANNOT make an energy beam or anything like that. Abstarct FICTION CANNOT act on objects. Can SPINDLY act on an object? Can “spindly turn into Reggie Miller. NO. Not a single erg or calorie EVER became physcial; tissue- it is abstract FICTIONAL unit.Feynman HISMELF called caloies FICTIONAL- INVENTIONS.

      Energy is strictly a totally abstarct characteristic. It is not itself… ANYTHING, people! I talk to world class physicists. I get SO tired of the Blogosphere misrepresenting this issu!!!!!

      In physics “laws” are NOT sacrosanct rules. Nor are they mandats set upon Nature from humans. Nor are they restrictions on the behavior of matter. NOne of you people have the slightest clue. Legendary physicist, David Gross, ( who highly admires Taubes) would straigten you all out. Feynman would have straightened all of you out. Physcists hate the term “law”. The laws are NOT the observations, the observations and the exp[eriments are ALWAYS inaccurate. AL we have are totally tentave, fallible BEST GUESSES from humamn beings that have been put theirugh the sieve a bit.This is wjhay “alws are. Actually, physicists call laws pictures, models or THEORIES. David Gross himself said this!

      Can we infer from the “laws” of thermrodynamics the behavior of mammalian fat cells. The answer is “hell no” !

      I have news for you people: Physcists uinderstand we AL;READY live in a universe where enertgy is NOT conserved. This principle the conservation of this NUKBER wer call “energy” is NOT conserved in the case of the rapidly expanding universe. It does NOT hold on the vast cosmic scale, nor in certain situations in General Relativity ( as Sean Carroll notes) . G.R. is actually MORE fundamentla than the “laws of thermodynamics” as is the Standard Model.

      As WEINBERG HISMELF notd, t he laws of thermodyanmcis DO NTO EVEN APPLY to some situations.
      They DO NOT apply to all situations. Sometiems they DON”T The laws opf thermodynamics ONLY apply IF we can DEDUCE something MORE FUNDAMENTAL that we know about that given system. KNOW THIS.!!!!

      What is thsi FETISH every salesman has for MISUSING MISAPPLYING MISREPRESENTING themrodynamics? I have the info from the BEST thermodynamics expert in thee world, Dr Gabin Crooks. He states , “obesity is a complex BIOCHEMCIAL ISSUE best understood under THAT framework, it is NOT a themrodynamics issue!!!!!!! Hear that loud and clear, everybody! Please educate yourselves!

      tHERE IS NOTHING special about :”calories They are INVENTED FICTION. NO such entity in Natuire exists. There is nothing ionstrinsic to food about them either….. Peopel eat MATETR,F OD, ATOMS. The EXCRETE AND REMOVE CARBON ATOMS. MATTER, STUFF. Calories had NO causal role- THEY CANOT ACT!!!!!! NOR are they the actual mechanism of gaining tissue fat or muscle . Calories and energy are NEVER-ANY exlpanation or description for ANY phenomena. Weinberg and Feynman STRESSED energy is NEVER EVER EVER ANY soprt of description or ASNY mechnsim whatsoeverin any phenomeon.

      Thsoe with certain single gene defects BWECOME OBESE TOTALLY IRRESPECTIVE of the amount of food ingestedas Dr Jeffery Friedman stressed !!!!! ,. We see tumors, huge tumors in destitute poverty, we see severe obesity in destitue poverty as Taubes notes. We see world height record Guiness type GIANTS in Mozambique- one of the poorest copuntries woth very little to eat at all. We see peole GET FAT FROM CANCER DRUGS. we see former model get fat from brain TUMORS

      THE Calorie MODEL IS A FAILURE AND INSULT to iobesity victims . Ther is also evidence the law sf physcis that giovern the universe , tables, chairs, planets IS DIFFERENT than the physics that giovern biology. Closer To Truth had several top tier physcists discussing this!!!!!

      The WHOLE GOAL is to continually test these laws or principles and see if and how they are WRONG or not. As VICTOR STENGER NOITED,. the alws of physcis are NOT restrictions on the bajhvior of matter at all!!!! Rather, they are restrictions on how PEOPLE- HUMANS- can WRITE equations. Aliens MAY HAVE DIFFERENT MODELS thanus as BRIAN GREENE NOTED.

  • Zoe,

    You are probably already aware of these, but for other readers if they are interested:

    Can a weight loss of one pound a week be achieved with a 3500-kcal deficit? Commentary on a commonly accepted rule. Thomas DM1, Martin CK, Lettieri S, Bredlau C, Kaiser K, Church T, Bouchard C, Heymsfield SB. Int J Obes (Lond). 2013 Dec;37(12):1611-3. [PMID:23628852]

    Pennigton Biomedical Research Center – Calculators:

    Quantification of the effect of energy imbalance on bodyweight.
    Hall KD1, Sacks G, Chandramohan D, Chow CC, Wang YC, Gortmaker SL, Swinburn BA. Lancet. 2011 Aug 27;378(9793):826-37. [PMID:21872751]

    The National Institute of Diabetes and Digestive and Kidney Diseases – Body Weight Simulator:

    • Many thanks Thomas – I hadn’t seen the simulator, but I’ve got the rest. They highlight another important factor about any formula – time. The first study looks at an average of 9 weeks and it still fails at every level. The results would have worsened as time went on. I keep coming back to – I’m supposed to get to 6lb in less than a year on a 1,000 cal deficit?! I plotted the actual results of the Franz 2007 review of 80 studies (26,000 people) against the calorie formula at 4 years and they’re out by a factor of up to 70 and that’s comparing weight with what should have been lost in fat alone.
      Best wishes – zoe

      • If you were able to actually create a 1000-calorie deficit daily, well, yes, you would starve to death within a few months (no, of course, you would not survive long enough to reach a weight of 6 pounds). Creating the 1000-calorie deficit would become harder and harder as time goes by, but if you succeeded, yes, you would lose weight. You eventually would lose much more than 2 pound per week, as you would lose lean mass which contains much less energy than fat mass.

        What do YOU think would happen if you created a 1000-calorie deficit daily for a year?

        • I know what happens – I proved the formula wrong personally 30 years ago and have been fascinated by it since. Hence my finding your presumption that I didn’t try to find the answers for myself (plus some ill chosen words and general tone) rude and offensive.

          Benedict seems to have been the first to find out what happens with calorie deficit over weeks (Francis G. Benedict, Human Vitality and efficiency under prolonged restricted diet, (study 1917, published 1919).)

          Strang made an important contribution a decade later (James M. Strang and Frank A. Evans, “The Energy Exchange in Obesity”, Journal of Clinical Investigation, (1928).).

          Keys pretty much settled the debate in 1945-50 (Ancel Keys, The Biology of Human Starvation, (study 1944-45, report 1950).), which I blogged about here 4.5 years ago (

          Then we have Stunkard A. and M. McLaren-Hume, “The results of treatment for obesity: a review of the literature and report of a series”, Archives of Internal Medicine, (1959). George A. Bray, “The Myth of Diet in the Management of Obesity”, The American Journal of Clinical Nutrition, (September 1970). Rudolph L. Leibel, Michael Rosenbaum and Jules Hirsch, “Changes in energy expenditure resulting from altered body weight”, The New England Journal of Medicine”, (1995) and a classic from more recent years Marion J. Franz, Jeffrey J. VanWormer, A. Lauren Crain, Jackie L. Boucher, Trina Histon, William Caplan, Jill Bowman, Nicolas Pronk. “Weight Loss Outcomes: A Systematic Review and Meta-Analysis of Weight Loss Clinical Trials with a Minimum 1-Year Follow-Up”, Journal of the American Dietetic Association, (2007).

          The latter recorded WEIGHT loss at a mean of 3-6kg at 48 months. According to the calorie theory, FAT loss alone should have been 188.8kg at this stage.

          Try it! You say you have weight to lose and you’ve tried low carb, which suggests you wouldn’t mind losing weight. Create a deficit of 1,000 calories a day for a year and let us know if you become the first person on the planet to ever adhere to the formula.

          • The studies you link to did not create a 1000-calorie deficit. They lowered caloric intake by 1000 calories. This is a huge difference! I guess that is also what you mean when you say you “proved the formula wrong personally 30 years ago”. I guess you decreased you caloric intake and at some point you stopped losing weight despite your continued efforts. That’s what is supposed to happen. You reach a new caloric equilibrium at a lower weight, with a lower caloric intake (and lower caloric expenditure). You do not live in a perpetual state of energy deficit.

            Do you understand what I mean? That there is a huge difference between lowering your caloric intake vs creating a calorie deficit? The “calorie theory”, as you call it, is about calorie deficits. Now, I see in some of your quotes from governement website that some people oversimplify or misinterpret the “calorie theory”. Yet, every study I have seen where they actually create a calorie deficit (expenditure > intake) confirms pretty closely the idea that 3500 calories = 1 pound of fat.

          • Valerie writes that “The studies you link to did not create a 1000-calorie deficit. They lowered caloric intake by 1000 calories. This is a huge difference! …. You reach a new caloric equilibrium at a lower weight, with a lower caloric intake (and lower caloric expenditure).”

            But that is kind of the point of “debunking” the 3500 calorie argument, is it not? We’re frequently told to lower our calorie intake by nutrition/fitness experts who assume that doing so will NOT automatically lower our calorie expenditure. They make it sound like caloric expenditure is pretty much determined by your choice of physical activities (workouts, walking a lot, etc.) & not by homeostatic mechanisms you have no control over.

            If eating fewer calories does indeed _automatically_ result in burning fewer calories, then there is little point in cutting calories to lose weight. You’d just settle in at a new metabolism, & there’s no way to measure how many calories you’re burning daily, anyway.

            Yes, the studies Harcombe cites leave open the possibility that creating a “real” 1000-calorie deficit would result in the predicted weight loss. But since there’s no way for ordinary dieters to know when they are acheiving this, the advice is useless and misleading.

          • Emily, I agree with your view that the advice to reduce caloric intake will not cure obesity. But Zoe goes much further than that in her post. She seems to go after everything: the caloric content of a pound of body fat, the biology of energy use/accumulation, the eat-less-move-more treatment of obesity, etc. I’m not sure if she understands where the correct facts end and where the errors begin, or if she is blindly attacking anything with the word “calorie” in it. Her post and her comments leave me wondering.

            If we go back to Zoe’s quotes in the blog post, well, most of them are not even wrong! The quotes from the BDA and the NHS may not be terribly useful, but they are not false. Why attack them? I think the science is correct there.

            The NOS quote is definitely wrong. That kind of statement does more harm than good, and I believe the public would be better served if it were corrected. But after losing so much credibility with the rest of her rant, I don’t see how Zoe could be taken seriously and help change the public discourse.

        • Anyone who maintained a 1000-calorie deficit long enough wouldn’t be around to claim that it doesn’t kill you because they’d be dead. At some point they’d be at a point where an intake of less than 1000 calories would be needed to maintain their low body weight. After that, they’d have to not eat anything and exercise to maintain the 1000-calorie deficit, assuming they’re not already dead at that point.

          Some people are confusing lowering an existing calorie intake by 1000 calories and maintaining that calorie intake with the state of maintaining a 1000-calorie deficit. Someone lowering his calorie intake from 3000 to 2000 and maintaining 2000 will eventually reach a new lower steady body weight. In contrast, someone maintaining a 1000-calorie deficit will have to go from a calorie intake of initially, say, 3000, later to 2000, then 1000, 0, and eventually -1000 (zero calorie intake and 1000 calorie expenditure of roughly BMR plus exercise). The weight loss would get faster toward death as body fat was depleted and lean mass (lower energy density relative to fat) was used for fuel.

    • The paper by KD Hall is worth reading. It shows that a an extrapolated result of a static model over-estimates weight loss compared with a more accurate dynamical model. It mentions that some policy makers are promoting a soda tax by using a static model which overestimates the weight loss by a factor of five.

  • I have started your eating plan adn I am on to Phase two. My husband and I have both lost a few kilos already and it is a satisfying way of eating. And not so hard to follow. Also I have just been diagnosed as having type 2 diabetes. Probably had it for years too, but nobody checked and I feel so well. Since starting the diet I have felt more energised thatn I have for ages. The doctor told me he woudl give me 3 months to lose 5 kilos and get my sugar and cholesterol down. I don’t have high blood pressure – in fact one nurse said it was as good as an 18 year old’s. I have tested my sugar a few times now adn it fluctuates a lot. Do you think 3 months will be long enough to bring it down? I am not yet on any medications and hope not to need them.

    • Hi Dawn – there is a general trend in the medical world of redefining normal as high. A normal distribution means that it is entirely normal that the normal distribution curve will represent the normal population.

      Here is a link ( with a couple of very interesting graphs – open up figure 1 and figure 2. Figure 1 is the higher number when you have your blood pressure reading (the 140 in 140/90 kind of thing). This shows that the normal blood pressure range for the general population is anywhere from 90 to 240 as the top number, with 130 being the most common reading and the average being around 140.

      Figure 2 is the lower number (the 90 in the 140/90) and this ranges from 50 to 130. The most common is around 85 and the average is around 90. So the true average blood pressure in the normal population is c. 140/90. You may be aware that 140/90 is the definition of high BP! Normal has become high and then everyone who is now deemed high shall be medicated, when they are in fact normal.

      The same has happened with cholesterol – where the true – pre-statination – average used to be around 7-8 mmol/l. You will now be told that your cholesterol is high if it is above 5. It is in fact well below average at 5.

      I share this because blood glucose is another area where normal has been redefined as high. Here’s another interesting graph ( – this time American – so I’m not sure of your location but hopefully you can find an on line converter between mg/DL and mmol/l depending on where you are based. This one shows how much of the area above the true average has been redefined as high – no longer normal.

      So my first thought back would be – check that you really do have an issue and not just that you have become a statistic for the convenience and profit of drug companies. A healthy person is worth nothing – telling you that you are pre-diabetic makes you more valuable. Secondly – I think you are right to try to resist medication and especially if you don’t have a genuine blood glucose problem (which hopefully you can work out with the above). Metformin is the most common drug given to type 2 diabetics and I don’t have room to go into what it does here but it’s trying to ‘squeeze out’ any life left in your beta cells and what then? There are also weight gain issues with diabetes drugs (significant ones) and then you end up with a cyclical weight/diabetes/drug problem. It’s madness.

      I would be doing what you’re doing – trying real food, managed carb. I don’t know how long it will take for your blood sugars to become more stable and ‘normal’ – in the true normal range. They may be there already. I don’t think any doc would know this either – hence the sensible advice for you to come back after a time to check again. The less carbohydrate you consume, the better this is for blood glucose levels. Diabetes is the condition of being impaired in handling glucose/carbohydrate so why on earth are diabetics told to eat starch all day long? ( and (

      I hope this helps!
      Very best wishes – Zoe

      • Weight also suffers from the “redefine normal as high” rule. The actuarial tables for height and weight were originally calculated by insurance companies for the purpose of estimating life insurance risk.

        Since the 1950s those tables have been redefined downwards at least twice. So it was possible to go to bed a normal weight and wake up in the morning 10lb overweight.

        That’s not to say that obesity doesn’t exist, nor that it’s not a problem. Just as high cholesterol exists and can be a problem for some people (those with familial hypercholesterolemia for example), obesity does exist and can be problematic. It’s more that not everyone classified as “obese” by either actuarial tables or BMI is actually unhealthily heavy (or fat, if you prefer).

        Weight is, like most other human measures, more or less a bell curve. There’s more than one basic body-type (remember the old “ectomorph, mesomorph, endomorph” categories? When did you last hear of them?) And some healthy people will be fatter, or thinner, than other healthy people of the same height.

        We, as a society, are bordering on a collective eating disorder here.

        • Good point, Hugh!

          In addition, a) it matters where the excess weight is distributed (as in podgy thighs better than visceral deposits) and b) there are some ‘normal’ weight people who are less fit and less healthy than some who are a little overweight.

          I’m not saying the population isn’t getting fatter – they are, and worryingly so, but I like your point about the potential of a ‘collective eating disorder’ developing.

  • I think that the main point of the calorie matter is the fact that anyone deciding to reduce their intake by 500 calories per day to lose 1lb per week is going to be sadly disappointed. As Zoe has stated several times, if it were true, all of us serial slimmers would be dead before we’d lost the weight we need/want to lose! Our bodies clearly know nothing about mathematical formulae, and will respond as they see fit to a calorie deficit, and this response is different for everyone. I offer myself as an example. I joined a well-known weight loss organisation in May last year, purely to support my husband in his chosen method of weight loss (he wanted to lose weight for health reasons). At six months’ membership, I had lost a total of 24lbs. At one year’s membership, I had lost 24lbs. In the last six months, I have gone up and down the same four or five pounds. I ended my membership last week, mainly for financial reasons, but also because I’ve had enough of it. I am going to resume Zoe’s excellent “eat real food” programme, and I have no doubt that I will be able to at least maintain my 24lbs lost. I say that quality of calories is what counts, not the quantity.

  • Of _course_ the formula’s wrong. 1 lb is clearly approximately 9.77e12 kcal. (Dumb physics joke, for which I feel no shame.)

    More seriously, I have no problem using 3500 kcal as a zeroth order approximation for the amount of energy stored in 1 lb of adipose tissue. That respects that the number is a rough estimate in absence of any other information, yet it’s also a far cry from saying 3500 kcal = 1 lb weight loss.

    Also, from the DOM UK Committee quote: “… so to lose 1 lb of fat weight per week you would need an energy deficit of 7000kcals per week, or 500kcals a day.” I think that’s just a math error on their part, as the 500 kcal/day works out to 3500 kcal/week rather than 7000. It still doesn’t provide any support for the rule, though.

    That said, I’m not disagreeing with you at all. Mostly, I couldn’t pass up that joke.

  • Hi Zoe, thanks for bringing up this important topic again. Here’s a great article,

    Why is the 3500 kcal per pound weight loss rule wrong?
    KD Hall and CC Chow

    Int J Obes (Lond). Author manuscript; available in PMC Dec 11, 2013.
    Published in final edited form as:
    Int J Obes (Lond). Dec 2013; 37(12): 10.1038/ijo.2013.112.
    Published online Jun 18, 2013. doi: 10.1038/ijo.2013.112

    We welcome the recent article by Thomas et al.1 criticizing the commonly used 3500 kcal per pound weight loss rule. This echoes our research showing that the 3500-kcal rule leads to overestimation of weight loss in individuals and populations.2,3 Despite our agreement with the spirit of the article, we believe it has the potential to generate confusion about exactly why the 3500-kcal rule is wrong.

    The most serious error of the 3500-kcal rule is its failure to account for dynamic changes in energy balance that occur during an intervention. Unfortunately, we feel that this error is obscured by the equation of Thomas et al.1 meant to represent the predictions of the 3500-kcal rule: W(t) = W0 + ΔEB × t/3500, where the change in energy balance, ΔEB, was defined as the difference between the rates of energy intake and expenditure. What the authors failed to stress was that they calculated ΔEB as the initial difference between the energy intake and expenditure rates and assumed it to be a static quantity. In reality, ΔEB is dynamic and, if accurately estimated over time, then the above equation provides a reasonable estimate of weight change.

    Mathematical models attempt to correct this deficiency by estimating the dynamic changes in ΔEB.4 Thomas et al.1 correctly demonstrated that the typical assumption of a static ΔEB leads to exaggerated weight loss predictions with no plateau. However, the static ΔEB assumption was not explicitly stated and the reader may be led to the erroneous conclusion that the deficiency of the 3500-kcal rule is the numerical value ‘3500’.

    Conservation of energy requires that the cumulative energy deficit (that is, the integral of ΔEB) equals the energy lost from the body. The 3500-kcal rule was motivated by calculating that a pound of adipose tissue stores approximately 3500 kcal.5 A more accurate accounting of body composition changes demonstrated that this value is appropriate for modest weight changes in overweight and obese people, but is an overestimate in others.6 However, using a ‘corrected’ numerical value for the energy content of lost tissue does not repair the 3500-kcal rule without also accounting for the ΔEB dynamics.

    • Hi Ken – many thanks for this – Kevin Hall has done some very interesting work in this area. I’ve got a few of his papers in my Endnotes. However, he’s still trying to find a formula and there isn’t one. When you look at the one study in this blog (the 12 people) sent by two different organizations, any possible formula is out by so much to make it absurd. The idea that I could cut back by 1,000 cals a day and weigh 6lb in a year’s time (actually 6lb in less than a year because that would be fat alone… actually be dead sooner than that anyway)… it’s just absurd. And yet publications (governments and magazines alike) still get away with perpetuating this nonsense “cut back by 500 cals a day and you will lose 1lb a week”. No you won’t!
      But I do like KH for his maths alone!
      Best wishes – Zoe

      • Of course, you’re right, Zoe – there is no formula. I’m just glad that someone of Kevin Hall’s stature is explicitly attacking the 3500 kcal rule at all. The whole article is amusing to me because Hall is criticizing Thomas for criticizing the rule in the wrong way, yet they are both wrong! It’s all just so entrenched that it’s hard for them to let go, but at least acknowledging that weight loss is not a linear function of caloric deficit is a good thing, no?

  • Valerie, low carbing might not be for everyone but if you try low carb high fat (LCHF) and don’t be fat scared you might succeed, given that you manage to get through the transition period also called carb flu, when the body changes from burning carbs (and using glucose as main energy source) to fat burning and using fat as the main source. Eat egg, meat, fish and seafood in moderation, vegetables low in carbs and plenty of good fat like butter, coconut oil and olive oil.

    • Hi Modesty,

      I am contemplating a ketogenic diet. I was not deliberately avoinding fat when I tried low-carb, but I did end up eating lots of protein. I know for sure that my hypertension completely disappears when I fast for a long time (21 [miserable] days of fasting a couple years ago reduced my blood pressure dramatically). I have had two difficulties when I briefly tried the ketogenic diet:

      1- Immune crash dow (I caught an ear infection, a cold and shingles whithin a week of starting the ketogenic diet the first time. Could be a coincidence, but seems improbable).

      2- Hunger (My hunger does not magically vanish. If anything, the very small, dense meals are less satisfying than higher carb fare. Could improve long term, I guess).

  • “Hi Valerie – you must be a dietician. You have that unmistakeable blend of arrogance, ignorance and closed mindedness.”


  • Valerie – do you realise that by conceding that energy expenditure decreases as weight is lost through reduction of calorie intake, you have also conceded that the “calories in, calories out” principle is nonsense? The principle rests on the assumption that “calories in” and “calories out” are independent variables. As you have acknowledged, this is not the case – they are dependent variables. Obviously cutting “calories in” is futile if by doing so you also cut “calories out”.

    Zoe of course is well aware of all this – she links to a post on the Minnesota Starvation Experiment on her home page.

    (Though Zoe I wonder if your response to Valerie might have been a bit more measured, in the interests of getting your message across).

    • Hi Andrew – it probably should have been, but then the use of words like silly and troll are not used by someone trying to start out in a positive way! Plus – as you kindly point out – the suggestion that all I needed to do was search pubmed was one rolled eyes too many. I wrote a 134,000 word book on obesity with 400 references – I didn’t just challenge the 3,500 theory on a whim!
      Best wishes – Zoe

  • Hi Zoe,

    Thanks for the charming reply.

    The reference I linked to was the first one that popped up on a simple Google search. I read the abstract, did some simple math (they give weight loss and its composition, and I roughly estimated the calorie deficit) and it come pretty darn close to 3500 calories per pound of fat lost.

    My point was that you didn’t seem to even try to find the answers yourself. It is unfortunate that the “calorie theory” got distorted into simplistic advice on the site you mention in your post. Yet, the theory has been verified in metabolic ward studies. 3500 calorie deficit produces pretty close to 1 pound fat loss. Here is another one that finds the same thing:

    For the record, I am not a dietitian, I am just a fat person who tried the low-carb diet after reading Taubes. I got no benefit whatsoever from the low-carb diet, but my interest in nutrition science (or lack of it) remains.

    • Valerie – the study you refer to here only lasted 2 weeks. In longer term studies, weight loss falls well short of that predicted by the calorie principle.

      The problem with trying to lose weight by creating a calorie deficit is that we lose muscle as well as fat and our metabolic rate goes down. When we start eating normally again, because of the lowered metabolic rate (and also because our eating tends to get out of control as the body responds to the end of semi-starvation) the weight goes back on (this time all as fat) plus more, so we end up fatter than we were before. As an alternative of course we can try an continue semi-starving ourselves for the rest of our lives, but few people are capable of that, and what a miserable existence anyway.

      But I suspect I’m not telling you anything you don’t already know.

      I’m sorry you have tried low-carb and found it unhelpful. However I think you started in the wrong place. Taubes is a great writer with brilliant insights, but I wouldn’t look to him for practical advice. If what you followed was the diet at the end of “Why We Get Fat” then I’m not surprised it didn’t work for you. 1 cup of this, and 2 cups of that, no more than 6 olives a day (why?), counting carbs gram by gram, artificial sweeteners that stimulate the insulin response and cause sugar cravings etc etc. And at 20g of carbs a day it is quite extreme – I certainly couldn’t have kept to it.

      Aiming for low carb is the wrong mindset – we should aim (as Zoe would say) to eat “real food”. Essentially this means eating what we evolved to eat – meat, fish, seafood, eggs, leafy plants, berries, etc. This necessarily results in a low-carb diet without us having to count anything. Consideration of carb content is only needed in order to assess whether a more recent addition to our diet is metabolically suitable – eg full fat yoghurt, butter, cream (yes); milk (not really); tomatoes (yes); potatoes (not really) – and even then no gram by gram counting is needed.

      For practical advice on diet I go not to Taubes but to the wonderful John Briffa. “Waist Disposal” is ostensibly for men, but equally applies to women; or alternatively there is “Escape the Diet Trap”. Following Dr Briffa, I have found, as have many others, that where food intake is concerned, focussing on “what” means that “how much” takes care of itself.

      • Hi Andrew,

        When I tried the low-carb approach, I had already been eating (mostly) “real food” for many years. I swapped fruits, grains and legumes for meat, cheese and butter. My weight didn’t budge (if anything, I gained a few pounds), which was disappointing, but what surprised me the most was that even my hypertension didn’t improve (low-carb is supposed to lower blood pressure even without weight loss, on average at least).

        I totally agree with you that semi-starvation is miserable. I would even say it is unhealthy (especially if we include mental health in the picture). And indeed, it is extremely difficult to maintain a calorie *deficit* over long periods of time (hunger increases and energy expenditure decreases for many reasons). Still, in order to lose body fat, a calorie deficit needs to occur, and the 3500 calories per pound of fat is a pretty good approximation.

        I completely agree that it is false to say that you will lose 1 pound per week (indefinitely!) if you eat 500 fewer calories per day. That is a silly oversimplification. So, Zoe’s quote from the NOS is just plain wrong. But the quotes from the BDA and the NHS are mostly accurate. They may not be all that helpful, but they are not wrong. Zoe’s questions had easy answers (that she could find on her own), or they pointed easy mistakes (for which she could have suggested corrections). In any case, asking faux questions to government employees in charge of emails might prove their ignorance, but I fail to see how it is going to help anyone.

    • Yes, the experiment found mass loss matched expected according to initial Ein-Eout deficit. However, in order to show this, they used a low-carbohydrate diet. As we know from other experiments with low-carb diets, mass loss is not equivalent across diets, in spite of equivalent Ein-Eout deficit across diets. For example, in the A-TO-Z experiment, the 4 diets produced different mass loss while having equivalent Ein-Eout deficit. Thus, if the Boden experiment was repeated with a Standard American Diet instead, we can expect it to fail to replicate the results that were achieved using a low-carbohydrate diet.

      • In addition, the implication of the A-TO-Z experiment with regards to the Boden paper is that Boden must have tried his experiment several times – each time using different macro ratios – before he found the precise macro ratio that would produce the desired results. It’s highly unlikely that he stumbled onto the correct macro ratios by accident, the first time he performed the experiment, the only time he performed the experiment.

      • Martin, the A-to-Z experiment was in free-living people. We can’t know for sure how much they ate. More importantly, we don’t know what happened to their calorie expenditure. It is very plausible that diet composition affects energy expenditure (and hunger) at least in some people. So, eating 500 fewer calories does not necessarily lead to a 500-calorie deficit.

        • Thank-you Valerie for nicely summing up yet more reasons (as if we needed them) as to why basing a diet on calorie-counting is a fatally flawed approach :-P

          That was your intention… right?

          • Calories count, but counting calories is not a solution to obesity.
            However, pretending that calories don’t count is even worse.

  • Excellent follow-up, Zoe – keep at it!
    (I do keep saying this, and people nod along with me… and the next day they are saying, ‘Oo, I can’t have X with all those calories’… How to get the message across?!)

  • To Steven Kelly: “If you want to lose weight, eat less (and exercise more).” I can’t believe you said that on this blog. LOL! Are you sure you aren’t Marion Nestle?

  • Right on, Zoe. I’m with Tyrannocaster in that I admire the way you persistently try to get to the very bottom of things to find out their origins–especially from the sources you contacted (not harassed). They should know these things as we are the ones who also support their work. I would also like it if they just admitted there are many variables and that the 3,500 calorie ‘rule’ is an approximation at best, and it should always be noted as such, or gotten rid of altogether. Keep up the excellent work!

  • It is rather sad that nobody had the references on hand. However, there is no real controversy. Metabolic ward studies have been done, and the calorie-deficit method does produce the expected weight loss. A simple search on Google Scholar turns up references right away. Here is one of them (I used “calorie deficit weight” as search words).

    Your examples are silly. The 500-calorie deficit has to be maintained for one pound of fat to be lost every week. The key word here is deficit. As you lose weight, your energy expenditure decreases. I am pretty sure you know that. And I am pretty sure you are able to find the metabolic ward studies yourself. Harassing government agencies might prove that the employees are ignorant (or that your emails have been flagged as trolling), but it does not prove that the energy conservation theory is shaky.

    • Hi Valerie – you must be a dietician. You have that unmistakeable blend of arrogance, ignorance and closed mindedness.

      You have sent one reference, which proves that in 6 subjects, with 3 different interventions, lasting just 10 days each, the weight and fat lost were different. They adhered to no formula, let alone the 3,500 calorie myth.

      Thank you for sending yet another study that proves my point, but the request at the end of the post remains the same – prove this formula or stop using it.
      Best wishes – Zoe

    • Hi David – got it thanks – it’s where the upper limit comes from – see my reply to Phil
      Best wishes – Zoe

  • Well, the point is good that its too simplistic to suggest you will lose weight by restricting a certain number of calories. And yes, they should stop repeating that suggestion to people if it has no basis. But on the other hand, its a more ‘digestible’ message than something like,
    “If you burn 3500 calories a day due to thermogenesis, muscle movement, and other bodily processes and you stay in a room that is 70f all the time and all other variables that we may or may not know about are equal, then reducing caloric intake by 500 calories a day should equal 1lb of body fat lost per week.”

    I mean, there must be some equation like,
    Weight change = Calories in – calories shat (poo burns yo!) – calories for heat – calories for exercise – calories for normal biological processes.

    I’m no expert so what else did I leave out?

    • Hi James – what you left out is how you flit between energy and weight interchangeably because you can’t. Thermodynamics (and most people misinterpret the first law and forget to account for the second) says NOTHING about weight. It’s about energy. More accurately, it’s about the movement of heat. Weight = weight. Calories = energy.
      Best wishes – Zoe

      • Actually you can “flit” between weight (mass) and energy…hence Einstein’s theory of relativity: E=MC^2 is the same as M=E/C^2

        • Hi Tom,
          If that is your belief, how would you explain the thermodynamics, or Einstein’s hypothesis (which was initially base on light energy), to a power station, where thousands of tons of mass (coal) are converted to weightless energy (electricity). Is this reversible (can the electricity be converted back to coal, or gas, or oil, or some other mass based energy source)? Can we simply ‘flit’ between mass and energy in this scenario? If so. How does it apply to the human body?

          • Wow.

            Professor Andy just poo-pooed mass-energy equivalence…
            …a key conclusion from the theory of special relativity…
            …possibly the most thoroughly tested and validated theory in existence…
            …tested by a century of the most brilliant minds on the planet.

            But what the hell does all that count for. Andy’s gut tells him he’s right. And Andy is obviously really smart and modest.

            So take that Tom! (and Einstien, and Bohr, and Plank, and Schrodinger, and Heisenburg, and Feynman, and…)

  • I really enjoyed this post. What’s kind of scary is that the calorie theory relies on complete ignorance of two facts that seem self-evident even to myself, with very little training in physiology or biology. 1) All calories are not created equal – for example, the body responds differently to a calorie of fat compared to a calorie of carbohydrate. 2) Body metabolism changes based on amount of food eaten.

    It’s interesting how so many of these theories are based on ignorance. I think here of Malcolm Kendrick’s articles on why it is impossible for a saturated fat to be converted into cholesterol.

    Yet another instance of “Don’t bother us with the facts. Our minds are made up!” Particularly when there are massive industries predicated on that ignorance (e.g., statin drugs, weight loss).

  • Great that you’re pushing them to produce actual scientific evidence. I agree with fredt’s comment, though: If you want to lose weight, eat less (and exercise more); if you eat more than you need, you risk putting on weight. Anything more specific than that runs a serious risk of being too complicated, not applying to everyone or even most people, and being overturned by subsequent investigation.

    The mechanisms by which we lose or gain weight are not well understood at all. The media, those who make a living or a name for themselves on health issues, and even the scientists who let their research be simplified to the breaking point to get it in the news – all these are guilty of watering down the little we actually know with so much popularization and “expert advice” that nobody really believes anything they hear anymore.

  • If eating or not-eating 3500 calories equaled a pound of fat, I would weigh 1/4 what I do. I think the larger one is, the more the ‘calorie theory’ becomes ludicrously unrelated to whatever is going on.

    I once thought that I could so easily disprove that theory given the way my body works, but then I remembered that allegedly all fat people, without exception, lie about their food according to research. I remember seeing a ref on Dr. Sharma’s blog a few years ago to this study where all the overweight people — these are completely separate unrelated people mind you — over the course of weeks of the study, allegedly lied about what they ate, but the real kicker is, they allegedly all ate — and lied about — precisely the same number of calories every day! IMO this is nearly impossible to do with a bunch of separately living independent people even if you TRIED. It beggars belief that nobody even questions this.

    Allegedly the gut biome can make the calories absorbed or not absorbed vary up to 500 per day — while resistant elements make FFA’s in the gut. Why does this never get mentioned when talking about calories? They’re willing to make people obsess on 22 extra calories a day but their own body internally could make things vary by 25 times that?


  • While I don’t hold with the folk theory of obesity that 500 cals a day will turn into 1 pound a week of weight loss / gain, I do think the average or typical energy equivalent of lost adiposity has a basis in science from Wishnofsky in 1958 with references to Strang et al from 1928

    • Hi Phil – Many thanks for this. I reference both of these in my obesity book:
      “James Strang and Frank Evans (1928) observed that obese patients get hungry on calorie restriction diets and their energy expenditure ‘diminishes proportionately much more than the weight’.” (James M. Strang and Frank A. Evans, “The Energy Exchange in Obesity”, Journal of Clinical Investigation, (1928).)

      The Wishnofsky is where the upper 3,750 cal limit comes from. He refers (in the article you nicely reference) in turn to Bozenraad: “It was shown by Bozenraad that the average fat content of human adipose tissue taken from various parts of the bodies of well nourished subjects is 87 per cent. One pound (454 grams) of human adipose tissue, therefore, contains 395 grams of fat. The caloric value of one gram of animal fat is 9.5; consequently, the caloric equivalent of one pound of human adipose tissue may be considered to be about 3,750 cal.”

      Wishnofsky took that as fact but the 1911 Bozenraad article gave the range of fat content in adipose tissue as anything from 72-87% (Bozenraad, Deutsche Archives Internal Medicine, (1911).), which is what I used in establishing a range. The range could be even wider with other references, but the point had been made.

      Best wishes – Zoe
      p.s. the earliest source of the theory I found was Lulu Hunt Peters 1918 (Lulu Hunt Peters, Diet and Health (with key to the calories), published by Chicago The Reilly and Lee Company, (1918).) but this offers no proof – just states as fact “Five hundred Calories equal approximately 2 ounces of fat. Two ounces per day would be about 4 pounds per month, or 48 pounds per year. Cutting out 1000 Calories per day would equal a reduction of approximately 8 pounds per month, or 96 pounds per year.” Really?!

  • But to prove it, they would need to understand the variation in biological conversion of carbohydrates, excess protein and fat into energy, and to the variation in the forms and concentration of storage. We each have personal values of the Atwater factors. Atwater through out 1/2 his data because it was scattered so bad, it must be wrong. They would also need to account for hysteresis, which makes the math real interesting to work with.

    Do you really expect administration to deal with the complexities that they do not understand or with reality?

    All this make the maths near useless for anything beyond direction of change. Eat less than you are currently eating and your metabolism slow and starts to conserve, body temperature drops, energy drops, motivation reduces, and you may lose weight or not depending on the body. Reverse for the opposite. But what do I know?

  • Zoe, this is simply awesome; I really admire your tenacity with this thing. It would almost be funny it the issue weren’t so serious. It really is an emperor with no clothes clothes on.

    Please keep it up! Thank you so much.

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