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Horizon: Sugar vs. Fat

The big news story last week was an experiment done with identical twins on the BBC Horizon programme. A friend of mine, Kate, found an interesting twist – this was not a new experiment for Chris and Alexander (Xand) Van Tulleken.

A 2008 Channel 4 programme followed the brothers, both doctors, travelling to Chukotka (the farthest northeast region of Russia) to do some experiments. Chukotka is an icy peninsula, washed by the Bering Sea, a section of the Pacific Ocean, and part of the Arctic Ocean. It covers a vast area, but with a population of 55,000. It is one of the increasingly rare parts of the world where people can still be found living a primitive lifestyle.

Episode 3 of series 1 shows Chris following the local diet of whale, walrus & seal (with a bit of reindeer for variety!), while Xand follows a processed food diet from the only store selling ‘western’ food in the region. The last four minutes of the programme descends into the astonishing medical ignorance, shared by 99% of doctors, that HDL and LDL are good and bad cholesterol respectively (they are not even cholesterol). The twins get terribly excited that Chris’s ratio of ‘good’ to ‘bad’ cholesterol gets 30% better, while Xand’s gets 30% worse. Relative risk errors, causation vs. association thus compound not knowing the difference between lipoproteins and cholesterol, but the conclusion is that Chris’s diet was the best. Chris’s diet was high in fat and protein and devoid of carbohydrate.

Horizon on Wednesday 29th January 2014, was billed as a unique experiment to test whether or not sugar or fat is worse for us. Arguably the original experiment was best – real food vs. processed food. High fat vs. high carb. How we used to eat vs. how we eat now. It had all the right ingredients, but let’s look at the recent Horizon programme.

The Experiment

The idea was very simple. Chris was given a virtually fat free/high carb/sugar diet for one month, while his identical twin, Xand, was given a virtually carb free/high fat diet for the same period of time. It was also pitched a bit as America vs. the UK, as America is starting to think that sugar is the baddie and the UK still thinks that fat is the baddie.

Enter Amanda Ursell, nutritionist, who lays out visually on a table what the two brothers can eat. I was highly amused to see Amanda lay out Chris’s table – explaining that all of this food “bread, bagels, pasta, rice, potatoes, any description of breakfast cereals and unlimited fruit and veg ultimately breaks down into blood sugar“.  And she’s right. And that’s the main point that public health advisors just don’t get. They are telling us to cut down on sugar, while advising us to eat more carbohydrate. Carbohydrate is, or breaks down into, sugar.

With the jelly/sweets and other fat free junk Chris was allowed, his table looked remarkably like the government eat badly plate: 33% starchy foods; 33% fruit & veg; 8% junk and he just needed beans/pulses as non dairy protein and low fat dairy and he’d be on the perfect public health diet.

Xand’s side of the table featured cheese, meat, butter, burgers, chicken with the skin on, double cream, mayonnaise, etc. Immediately we see a problem stemming from nutritional ignorance. Xand is not allowed vegetables, but he’s allowed unlimited dairy – which, as rule of thumb, is approximately 5% carbohydrate (hard cheeses and fluid dairy defining the extremes). Burgers invariably have wheat, starch, rusk and/or sugar. Xand is seen later in the programme having meat slices, which invariably contain dextrose/sugar and mayonnaise invariably contains sugar, so Xand could also have been having sugar/starch inadvertently.


A couple of extreme experiments are done to test brain and body function in the twins. Stock broking is used to simulate a brain test and the brothers go out with the Team Sky cycling coach, Nigel Mitchell, to test the body. There are two fundamental problems:

1) The brain will fuel on glucose or ketones, if glucose is not available. The body will fuel on glucose or fat (dietary or body) if glucose is not available. Xand is unlikely to have been in ketosis/fuelling from fat if he is having carbohydrate in dairy products and processed meats/sauces. Xand does well considering that his body is not being given a fair chance to compete on an alternative to glucose.

We’ll come on to the results soon, but the fact that Xand started at a body fat percentage of 26.7% and only lost 3.5kg tells me that he was not in ketosis. I would have expected Xand to lose that weight in one week, not four, if he were genuinely on a zero carbohydrate, ketogenic, diet.

2) It takes time for the body to adapt to ketones/fat when glucose has been readily available for 35 years. (The Daily Mail article has their age). Expecting Xand to perform as well on new fuel, as his brother does staying on his life time favoured fuel is unreasonable.

Performance, however, was not what worried the general audience. The two issues that worried people on twitter, and that I received a number of queries about during and following the programme, were:

1) Muscle mass;

2) Insulin production and type 2 diabetes.

Let’s look at each:

The results – muscle mass

Xand started off at 26.7% body fat and Chris at 22.6% body fat. Both pretty flabby – as the mug shot photos confirmed. Approximately 36 minutes into the programme, the results are shared:

Xand is told that he lost 3.5kg (approximately 8lb) and this is said to be 1.5kg of fat and 2kg of muscle. Chris is told he has lost 1kg – also claimed to be half fat (0.5kg) and half muscle (0.5kg).

The BodPod measures fat mass and fat-free mass. More accurately, it measures air displacement and fat mass and fat-free mass are estimated from prediction equations (thank you Dr Chris Easton – @easto82).

I have written to Horizon asking them the following:

Dr Richard Mackenzie says to Xand “You’ve lost 2kg of muscle mass and that isn’t so healthy.”

Please can you help me understand how the statement to Xand can be made? My understanding of the BodPod is that it can measure fat mass and fat-free mass. Thus the programme can estimate (within the accuracy of the BodPod) how much fat has been lost and how much fat-free mass has been lost but the latter is not all muscle. The latter will include water and it is virtually guaranteed that water will be lost on a low carb diet, as glycogen will be depleted and water is stored at approximately four parts to every one of glycogen.

I look forward to your explanation

I’ll let you know the reply.

The results – blood glucose

The programme repeats the blood tests done at the start of the experiment – first testing cholesterol. Chris narrates “We thought that, because Xand was eating so much fat on his diet, his levels would be so much higher. What is amazing is that they were nearly exactly the same as they were at the start of our diets. In fact, there was little, or not change, for either of us.”

What is amazing is how quickly they glossed over cholesterol! No difference so, instead of exploring this, they just ignored it. I would have expected measurements to be different simply because of the known margin for error in the cholesterol test (c. 15%). Chris (if not both brothers) had a prejudice (literally to pre-judge) that Xand’s cholesterol would “be so much higher” and yet it wasn’t – explanation please?!

The final test was insulin – a hormone that regulates blood glucose levels. The programme didn’t explain what was happening at this point but it looked like the brothers were doing a glucose tolerance test. This involves the ingestion of a glucose solution and then blood tests measure subsequent blood glucose and insulin levels. Dr Richard Mackenzie said to Chris (the carb twin) “Your body’s ability to produce insulin improved.” The doctor brothers found this counter intuitive. So, Mackenzie went on to say “Your body has probably just got used to dealing with the sugar, the glucose intake and therefore responding by producing insulin.” Chris’s take on this is “Because I’ve been eating loads of sugar I’ve become better at managing it.” Mackenzie corrects with “You’ve become better at producing insulin.”

Xand asks if this is good or not and Mackenzie says in the short term it is good, but in the long term it might produce a problem. You’re not kidding! The long term likelihood is type 2 diabetes. When the body says ‘enough is enough’ – I cannot cope with this intake of carbohydrate/sugar anymore. I cannot continue to produce enough insulin to bring my blood glucose back into the normal range and I cannot do it with the frequency with which you are chucking carbs into me.’

Then we turn to Xand and he is told that “Your body is not responding to insulin as well as it did. If you eat too much fat, that can stop your body responding to insulin [how?!] and it can also tell your body to produce more glucose” [again how?! Is Mackenzie confusing the presence of fat with the absence of carbohydrate?] Mackenzie continues his warning [in a very worried tone] “your blood glucose has climbed from 5.1, which it was before the diet, to 5.9. Now you’re only 0.2 away from being pre-diabetic.”

I have three points:

1) There is a known 20% margin for error in blood glucose tests. Xand’s first test of 5.1, with a 20% margin of error, could have been anything between 4.1 and 6.1 and hence his second reading is well within the known margin of error. His fasting blood glucose levels could have gone down over the month and we would not know this because of measurement margins for error.

2) Xand has had essentially no glucose for one month. He’s had small amounts of lactose in dairy products and some starch/sugar in processed meats/mayonnaise etc, but he’s had very little glucose to deal with. He’s then been subjected to a glucose tolerance test, which would give him a massive dose of glucose in one hit. The carb twin, Chris, is not surprisingly able to cope with this (produce insulin) because that’s what he’s been doing several times a day for one month. Xand’s body is going to need time to adapt back to glucose just as it needed time to adapt away from it.

3) Xand is not pre-diabetic at 5.9, notwithstanding margins for error etc. Normal blood glucose levels have been redefined, just as normal cholesterol levels have been redefined, just as normal blood pressure levels have been redefined. Healthy people are non-profitable. Sick people are profitable. The more people who can be placed in a ‘sick’ category the better.

In 1999, the World Health Organisation announced a “major change” in the diagnosis of diabetes. The diagnostic level of the fasting plasma glucose concentration would be lowered from 7.8 mmol/l (140 mg dl) to 7.0 mmol/l (126mg dl) and the whole blood level benchmark would be lowered from 6.7 mmol/l (120 mg dl) to 6.1 mmol/l (110 mg dl). Over one million Americans became ‘diabetic‘ overnight.

“The meeting was made possible by generous financial support from Bayer, UK; Bayer, Germany; Novo Nordisk, Copenhagen, Denmark; and The Institute for Diabetes Discovery, New Haven, USA”. I bet it was!

The conclusion

Xand concludes “Basically what I get out of this is – I have to avoid the processed food: the doughnuts; the ice cream; the cheesecake. That sort of 50:50 fat and sugar mixture I cannot stop eating and that’s the problem.”

Clearly I like any conclusion that says don’t eat processed food. Spelling out – “Eat Real Food!” would have been even better. Xand needs to stop at the first part of his conclusion as well – avoid processed food full stop. Not just the 50:50 fat and sugar mixtures, but the breads, cereals, bagels and starchy foods that adorn the government’s ‘eatwell plate’.

It would have been better still if Xand, as a 10 year doctor/6 years in medical school, could have explained why fat and sucrose combined are so bad for humans. It’s because real food doesn’t contain both – with one exception – avocado. Nature provides carb/proteins (any real foods that Chris was eating) and fat/proteins (any real foods that Xand was eating). It’s food manufacturers who have worked out that the sucrose/fat combo is irresistible, moreish and fattening – to rats or humans. That’s why fake food needs to be avoided.

Chris’s conclusion was “Where I end up is all faddish diets – all faddish diets – are wrong and misguided. And doing exercise is really important.” [how did an exercise conclusion follow from this experiment?!]

The “don’t eat processed food” message had already been lost with 15 minutes of the programme left.

The bias

The BBC is supposed to be balanced. This programme was not balanced and the bias against fat is so ingrained that the BBC may not even have realised this.

The mind (stock broking) experiment was presided over by Professor Robin Kanarek. Her views were very clear – “glucose is the best fuel for the brain“; “memory will be significantly compromised without enough carbs in the diet“; “a high carb diet will facilitate memory” and so on. Why was Dr Emily Deans not the expert on hand? “Ketosis for the body means fat-burning (hip hip hooray!). For the brain, it means a lower seizure risk and a better environment for neuronal recovery and repair.” Or even – why not have both Kanarek and Dean to provide balance?

The body (cycling) experiment was presided over by Nigel Mitchell from Team Sky cycling. He favours porridge for breakfast and states “your body needs the sugar. It needs the carbohydrates“. Why not balance him with Peter Brukner, the low carb/high fat coach celebrating a 5-0 Ashes victory with the Australian cricket team? Or Djokovic’s gluten-free coach?

Dr Robert Lustig, the current lead global expert on sucrose and fructose (who pays tribute to Professor John Yudkin from decades earlier) was interviewed. I was surprised and disappointed at how quickly Chris dismissed Lustig’s input. This did not display a doctor who had gone into this experiment with an open mind. Chris dismissed the fructose studies claiming they had unrealistic intakes of fructose and tossed away “The insulin hypothesis” as untested.

I had the privilege of seeing Dr Richard Johnson  present on the topic of fructose in 2009. On his opening slide he showed a typical continental breakfast tray with 40 grams of fructose in the cereal, juice, fruit, jam, croissant and coffee. And that’s just breakfast. The points being made by sucrose & fructose experts (not infectious disease – Chris), such as Johnson and Lustig is that normal sugar consumption is now abnormal and humans are paying the price with obesity, type 2 diabetes, cancer, heart disease, Alzheimers and so on. As for the insulin ‘hypothesis’ – the lipid hypothesis is also unproven. Indeed the COMA report openly admits: “There has been no controlled clinical trial of the effect of decreasing dietary intake of saturated fatty acids on the incidence of coronary heart disease nor is it likely that such a trial will be undertaken.” (COMA, 1984).

When Professor Susan Jebb was interviewed, however, there was no subsequent dismissal. Indeed the opposite happened. Xand reinforced Jebb’s views “And we’re in no doubt about this link – that being fat makes a lot of people ill.” “Absolutely“, says Jebb” it increases your risk of heart disease and cancer and of diabetes.” Jebb then describes her experiments that have looked at what Xand helpfully calls good fats (monounsaturated fats) and bad fats (saturated fats) [Puh-lease!] The final conclusion? Changes found were “modest”, “surprisingly small” when trying to look at the impact of different macronutrients or types of fat. This may explain why these experiments were useless.

I loved an insightful comment on Dr John Briffa’s excellent post on this Horizon programme. Check out ‘Jennifer’ who observed that “Lustig’s contribution was trivialised…..located in a fun fair with silly music (so he must be barmy)” while “Jebb was shown as a white-coated academic in a university setting (so she must be sensible).”

Lustig was the only anti sugar voice on the programme and the only expert dismissed before the viewer could digest his points. Amanda Ursell cautioned Xand that he would get bad breath and be constipated, but gave Chris no warnings about his sugar diet. Professor Kanarek was pro-carb, with no dismissal. Nigel Mitchell was pro-carb, with no dismissal. Richard Mackenzie issued severe cautions to Xand, but not to Chris.

Even the title of the programme showed bias. Instead of putting the foods in alphabetical order, the programme was Sugar vs. Fat. The people vs. Larry Flynt. The Crown vs. Ronnie Biggs. The party on trial is named second – that would be fat.

But then, the programme opened with Chris setting out the current belief “When I trained as a doctor it was clear that fat was the enemy because it raises your cholesterol, then blocks up your arteries causing strokes and heart disease” and that is one heck of a position to move away from. Sadly Chris represents 99% of the doctors in the UK – similarly entrenched in a dangerous and non evidence based mindset.

p.s. here’s a follow-up post

47 thoughts on “Horizon: Sugar vs. Fat

  • The fear of sugar is unnecessary. Not only have we seen clear evidence of what happens when someone eats a ton of carbs in this video – but we can look at your average American which SURE gets tons of sugar BUT also gets a ton of fat.

    The body PREFERS glucose but in the presence of high free fatty acids circulating in the blood the randle cycle takes over. The randle cycle basically mimics type II diabetes by causing the body to use fat for fuel.

    In fact – diabetes is caused by a state of high free fatty acids in the blood which causes insulin resistance. There is plenty of studies on niacinamide (NOT NIACIN), and even Ginger and Aspirin which shows that these substances inhibit fatty acid metabolism, increase the sugar metabolism and lower blood sugar levels and prevent diabetes.

    This article was clearly written by someone so far into denial that they can’t even see the crystal clear evidence right in front of them. What do te producers of this show have to gain by promoting sugar or fat over the other?

    • The average American gets 70% of their calories from soy, corn, and wheat, that is not tons of fat.

  • Zoe,
    What a breath of fresh air! I wrote a similar blog calling out the dumbed down and questionable “science” of Horizon these days. It was for Huff Post but their word count is so restrictive I let it go – there wasn’t space to do it justice.

    I am looking forward to your blog about the most recent travesty of Horizon’s What is the Best Diet, the 3 part series that aired this last week which was also full of dumbed down “science”, unanswered questions and imho wrong thinking at the most fundamental level of nutrition.
    Thanks for your work.

  • Thank you!
    I’ve just finished watching this documentary and I could not believe the conclusion that was reached. Thank you for calling out this misleading bullshit.

    • Crikey Zeny – I can’t believe the US has missed out on a chance to add sugar! UK mayo tends to have added sugar…
      Best wishes – Zoe

      • There’s actually ‘good’ and ‘bad’ mayonnaise – Helmans or home made generally has negligable carbs/sugar, but lower cost mayo in us/uk is much higher. Its so easy to make yourself though, and then at least you know exactly whats in it.

  • This is a really great article Zoe, thanks.

    I’ve been increasingly interested in nutrition over the past year or so and have recently read Dr. Lustig’s fabulous book ‘Fat Chance’ and David Gillespie’s book ‘Sweet Poison’. My eyes have been opened to the perils of sugar and the healthy or ‘real’ way of eating. The problem I have found is that when I tell other people about what I’ve learned, they dismiss the realities of a high fructose diet. I’m now trying to tell more people about what I now know through my blog. I don’t have a science or medical background, so my approach is a fairly light touch! I’m glad I came across your blog, I’ll be back for more.

    Sugary Desire –
    What does the WHO recommendation on Sugar mean to your daily diet?

  • Hi
    I am not sure why you think that Dr Mckenzie would be using a £10 Prodigy AutoCode Talking Blood Glucose Monitoring Meter Kit in his Laboratory at Westminster. As a scientist if he states that the readings is 5.1 then it is 5.1 unless you have any evidence to say otherwise .

  • I didn’t see the programme but I’m following your discussion with interest. As an ‘old school’ nurse ( I have worked mainly in cardiology) I have has never seen as many poorly controlled diabetics in my 41 year professional nursing experience as I do now. I (covertly!) followed the Atkins diet a few years ago. I lost about 3 stone. my lipids were unchanged and I felt great. I confess some pounds have crept back on as I slipped back into bad habits and I’m back on the low carb path. Good luck, Zoe.

  • Hi Zoe-

    Thanks for this review; I was totally irked by this program, and it was nice to read some words of wisdom. One more point I wanted to bring up: if Xand went quickly from a high carb diet to a very low carb diet, and lost water weight (as you rightly mentioned)- he probably also lost a lot of sodium and potassium at the same time. Ketogenic diet experts (like Dr.s Phinney and Volek, or Dr. Westman at Duke University)- recommend that in the interim, extra sodium, magnesium and potassium should be consumed, until one becomes keto-adapted. (As you mentioned, he probably never was fully keto-adapted, as he continued to crave carbohydrates). Anyway, there was no mention as to whether Xand was taking these extra precautions (probably not, as there were no low-carb experts on the show). Apparently, this loss of important minerals can make one feel pretty bad for a time, and would have also explained why he did so poorly on the mental and physical tests he was given….(although in addition, as there were no “control” tests- i.e., how well did each brother perform before they went on their various diets? We have no way of knowing if one brother were more talented, or in better physical shape than the other). I think the word “science” should not be used in conjunction with this show at all, but it makes me irate that some people may watch it and believe they’ve learned something.

    The bias was obvious, right from the words “the low carb diet will give you bad breath and make you constipated”. I personally find a low fat diet causes bad constipation (never had any problem on low carb), and refined sugar causes the worst breath of all. In addition, all of the things that are normally positive about a low carb diet they gave a certain “spin” to, to make them appear negative. I didn’t understand what was so “bad” about the low carb twin not being able to eat a huge lunch only 3 hours after eating a huge breakfast! No wonder he wasn’t enjoying his food, he wasn’t hungry yet. And if they were trying to find the answer to the obesity epidemic, well, wasn’t that the answer right there? In addition, they claimed that fat messes with the hormone ghrelin. But had they actually listened to Dr. Lustig, he would have explained that excess fructose actually dulls our sense of satiety; i.e., it’s the other way around, and it’s the lack of satiety that’s abnormal. But alas, I guess only so much information can be divulged at a fairground…..

    Well, I could go on and on, but I won’t for now……

  • Thanks so much for this Zoe. The program me drove me mad when I watched it as the experiment was so badly designed. This post is exactly what I wanted to say to my husband when I tried to explain all what was wrong with that program to him!

  • Good point, although arguably this is probably the only time this mix is provided to man and provides the most calorie dense food needed by the baby to sustain the phenomenal growth and development at the only time it is needed.

    Vital nutrients aside isn’t it the job of mothers milk to make the baby as ‘well fed’ or large as possible as quickly as possible to give it the best chance of survival? We tend to judge the health of a newborn by how quickly they put on weight, and I’m reminded of comments by the midwives when my son was born “he’s feeding well” “he’s gaining weight at a good rate” etc etc

    Maybe that is the problem today and if the mix of fat/carbs is indeed the problem then we have inadvertently created a nation of overweight and overfed adult babies consuming mothers milk equivalent waiting for a growth spurt that is sadly never coming!

  • Breast milk contains both fat and carbohydrate and is natural.

  • Thanks so much for your reply! I just read the Diet & Health Today article and it is a real eye-opener. Now I have another question.

    I’m confused about how available fat-calories really are to the body when it needs energy. From the article and your reply it seems that if we need energy and there are no carbs available at that moment, we will simply start burning fat (dietary or body) instead. But this seems at odds with what you say about Xand’s performance in the brain test. There, it looks like you are saying that Xand’s body could not access the fat-calories (even though he needed them in the short-term) because he was not in ketosis due to the presence of carbs in his diet.

    Is there a danger-area, a carb quantity range which does not provide enough in itself for energy, but somehow stops the body going into ketosis, blocking access to calories from fat? Leading to listlessness and poor mental performance?

    Thanks again, Naomi

    • Hi again – brain vs body. The brain needs glucose or ketones and Xand didn’t have sufficient levels of either. Check this.
      Best wishes – Zoe

  • Hi Zoe, I have just discovered your work and I find it fascinating.

    Please could you explain some more about how the body makes different use of sugar vs fat?

    In particular, a related point you make in another post – that carbs cannot be used for body maintenance, and are best placed for use in non-BMR energy expenditure through exercise. This articulated something for me – I’ve long suspected a major cause of obesity is that we are eating food our body can’t use for its vital processes and so we crave more and more.

    How much of the BMR is directly used in body maintenance? I’m guessing that some of the BMR is used to power the heart, and consumed in the brain, and other energy usages that can make use of carbs. I’m interested in how much of it HAS to be fuelled from non-carb sources.

    Could you point me to some facts and figures on this? Thanking you in advance – meanwhile I’ll keep reading!

    • Hi Naomi – I raised this concept in an article here and in a video here.

      The BMR is strictly the resting metabolic rate – we say to people to think of it as the calories needed if you’re lying in bed all day too ill to move. Yes – an element of this still includes fuel for even the tiny amount of movement that does take place, but the vast majority of what the body needs to do if we’re not moving, is managing the 9 body systems: nervous system; skeletal system; endocrine system; reproductive system; digestive system; circulatory system; lymphatic system; urinary system and respiratory system. Hence I’m trying to get people to think about food intake needed for repair/maintenance (think of this as closest to BMR) and food intake needed for energy.

      Then the Harris Benedict work (dating back almost 100 years ago) is still very useful. (I don’t normally quote wiki, but this is a good summary of the Harris Benedict equations.)

      Then – any biochemistry book will tell you about food metabolism – carbs, fats and proteins. Some nutrition books may get it right but most get it wrong and say that you need carbs for energy. We don’t. The body can use dietary fat (or body fat) for energy. It will prefer carbs – easy glucose – no doubt but we can fuel on fat. Fat is thus the most versatile macro nutrient – usable for basal metabolic functions and/or energy.

      I’ve not seen anyone else put these things together in the way that I have done – let me know if you do. Someone else should have worked this out too!
      Very best wishes – Zoe

  • Thanks Zoe for the great article, the programme wound me up too. One point about the cognitive test that the programme failed to mention and that was that Xang had recently taken a long haul flight to the U.S. and therefore would have been affected by jetlag. This would probably have affected his sleep patterns and as a result made it harder to concentrate!

  • I too saw this programme and thought it very simplistic. My husband did the ‘no carb’ thing for 3 months back when it was fashionable and lost weight but of course put it all back on (and then some).

    I think Sue must be eating way more than she says (“broken cookies don’t count”) as I am 60 and 17 years post-menopause and have lost 35 pounds in a year (with a club) by dropping junk food. I do eat non-processed carbs and proteins at the same time and did not exercise nearly as much as Sue, though once the weight was lost I took up Nordic walking.

  • Thank you Zoe, as usual – a faultless critique. So glad I’m not the only one (Kate) who gets raised BP when subjected to the deluge of health ‘misinformation’ these silly, low budget programmes present as ‘science’. I’m sure the many parents who sat their carb/sugar-addicted kids down to watch were thrilled to hear the message, loud and clear: “FOLKS…SUGAR AIN’T THAT BAD!”?

  • Totally agree. Very weighted programme. Even I as a lay person thought it was obvious re the insulin as he hadn’t beempn eating sugar. Hadn’t realised the bod pod didn’t actually measure muscle mass, good to know.

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  • In your discussion of fasting glucose you indicate that the fasting glucose level has been artificially lowered in order to sell more diabetic meds, similar to the lowering of “normal” cholesterol levels in order to sell more statins.

    I have never heard the accusation about fasting blood sugar levels. From my reading it seems that the lower the better for FBG. Do you think FBG of 140 is just as safe as FBG of 95? Sorry these are American levels. I have been after my carb addicted husband to lower his FBG or his health will deteriorate. I have gotten my information mostly from Blood Sugar 101.

    I am curious as to what FBG range your research deems to be healthy. Thanks

    • Hi Pam
      Good question! It’s certainly not the lower the better for any human measure (glucose, cholesterol, BP etc). We need some glucose in our blood stream or we’d be in a state of hypoglycaemia (low blood glucose). We don’t need too much or we’d be in a state of hyperglycaemia (high blood glucose). Both are unpleasant and potentially dangerous.

      I define healthy as what is normal in a normal (non messed around with) population. The link in the article shows the normal distribution of FBG levels. If I had the raw data I could work out the standard deviations to see where proportions of people fall (in a normal shaped distribution curve, 68, 95 and 99.7% of values fall within 1, 2 and 3 standard deviations from the mean respectively). Visually we can see that most people fall within the range 50-150 mg/dl. This means that it is normal for most of the population to fall in this range. My objection is when an intervention is made, following “generous financial support” from drug companies to say that normal is now deemed unhealthy. Normal for some people will be a FBG of 50. Normal for a similar proportion of people will be a FBG level of 150.

      Carb addiction is a separate, and serious, issue. The question is – what is your hubby’s normal FBG level when eating real food? And how stable does it stay (stability being arguably more important than different measurements) during the day and from one day to the next? Stable and normal may be 140 for him or 80 – don’t let drug companies tell you normal is abnormal (or, unhealthy) so that they can call someone diabetic!

      Hope this helps
      This could help with the food addiction (
      Very best wishes – Zoe

  • Hi there! I watched Horizon: Sugar vs. Fat; it was very interesting. It concluded that neither sugar nor fat on their own make you fat but, mixed together, they do! Apparently, there are ‘cut off’ switches in your brain which tell you when you’ve had enough sugar or fat but no switch for them combined. It was also noted that nowhere in nature does this mixture exist and it only occurs in processed foods – remind you of anything? I rest my case!!!

  • Dear Zoe,…over any years I have struggled trying to find a diet that suits me after being to many diet clubs & classes, with the results of only putting on weight not ever loosing any…I exercise regularly. I watched the program me the other day and am still confused, so could you tell me if my diet is a good one . Breakfast poached egg 2 grilled bacon rashers…lunch smoked salmon 1 small Advacado lettuce tomato cucumber…evening meal eith steak or chicken salad keaves..1 piece if fruit few grapes Banana Kychee..weekends but more relaxed with a couple of glasses of wine maybe Friday of Saturday…I exercise most days…TRX…spinning….Pilates…20 20 20….but no weight loss..,any suggestions…kind regards Sue

    • Hi Sue – we have known since 1917 that weight loss (through cal deficit) is invariably regained and more. It’s why the USA/UK/Aus and NZ have got bigger the more we have tried to diet. Here’s a blog on the definitive study to prove this.

      What you list looks pretty perfect – real food/managed carb intake. I suspect therefore a couple of things 1) what gets consumed when “more relaxed”! and 2) the impact of previous dieting history on your metabolism. Both are sortable – our club is here if you want help.

      Very best wishes – Zoe

  • Well they did state something of a universal truth. “six years in med school and we don’t know about this stuff” Sounds about right to me!

  • sorry that was 0.5 mmol/l (litre) not mmol/h. My ketones were higher sat watching it on the sofa.

  • The ketone data fleetingly visible on screen during the cycling segment (twice) showed a maximum concentration of 0.5 mmol/h. The carb guy was lower, of course, but with n=2 probably not statistically significant.

    I also concluded that Xand was not keto adapted, his brain ketone flux would have been much higher at 1 – 1.5 mmol.

    There is huge institutional bias in the UK – try finding a low carb dietitian on the BDA web site – only two have “carbohydrate” in their profile at all, and not in a low carb diet context. We needed two teams of experts with different viewpoints.

    The doctor who declared the muscle loss from a density measurement must be a hazard to be around, I wonder what other measurements he doesn’t understand.

  • “What is amazing is how quickly they glossed over cholesterol!”

    Yep, noticed this – so aggravating! I shall point this out to my doctor who wants me back on statins again.

    You comment on the fasting test – I’m confused by this anyway – HBA1C tests are surely done 3 months apart – that’s if your diabetes is uncontrolled. At 1 month, he is surely still recovering from the High Carb diet he was living on before.

    “[how did an exercise conclusion follow from this experiment?!]”

    I’m sure they chucked in an “exercise is important for losing weight” statement somewhere. They failed to ensure that people need to do the right kind of exercise i.e. slow, repetitive exercise, not the sort wehich puts your body into fight or flight response.

    “The body (cycling) experiment was presided over by Nigel Mitchell from Team Sky cycling.”

    Not sure why the experiment was conducted in this way anyway. It made me wince, since no sensible diabetic allows their sugars to drop to that level and then do strenuous exercise on top. I found this a highly suspect set up, and wonder if they were actually expecting the HF twin to collapse, thus showing the ‘dangers’ of a HF diet. I don’t believe any T2 following HF/LC diet would do such a bike ride without something more substantial in their pockets than 1 pat of butter. I would actually be carrying biscuits myself, out of fear of an extreme hypo. I know this relates to T2’s (I can’t comment on T1s, my knowledge is not good enough) but I don’t think either twin was doing anyone any favours.

    “that he would get bad breath and be constipated”

    Why not mention nuts? Nuts can be slotted into a low carb diet, and provide a small amount of fiber. As you have pointed out, the dangers of food passing through the body so quickly that their nutrients cannot be absorbed are probably extremely high, nuts would provide the right pace and yet did not seem to make any appearance at all.

    “Sadly Chris represents 99% of the doctors in the UK – similarly entrenched in a dangerous and non evidence based mindset.”

    Ah, I did read that slightly differently. The fact is that this current generation of doctors have indeed been trained in that mindset. The issue is that whereas we might expect to see people trusting to holistic medicines and faith healing with no evidence, when presented with facts, Doctors are the people who need to be saying, “Hold on, this jars with what we would expect to see. We should investigate”. Science is supposed to be the discipline which is excited by theories being proven incorrect.

  • Zoe. Marvelous response to BBC on our behalf, thanks.
    Having read your excellent books, along with Dr Briffa and Prof Lustig, the silly Horizon show still cast doubts in my mind that what i am doing may not be the healthy, correct thing, even though I know how well I am feeling on the regime. But, I soon overcame the doubts, and, in fact, it has made me more resolute in continuing LCHF way of eating. Not everone watching will have had the resources, or the time, to look below the superficial, and that is why Horizon must be condemned. I call it Junk Telly, in line with Junk food.

  • Thank you Zoe, Excellent breakdown from a real expert!

  • I agree with everything you have put in your article. A really well written critic.

    What a waste of an hour that was watching Horizon

    my diet is based on the primal blue print style of eating (Mark Sissons –

    I thought like yourself that the program was stacked against Fat and probably left the public believing that a high fat low carb diet would lead to muscle waste and type 2 diabetes. Where in fact the Doctor was on a high fat No carb diet, which of course over a sustained period of time will lead to physiological insulin resistance.

    Where is Michael Mosley when you need him?

  • Thanks Zoë,
    I sat there watching and for the first few minutes I thought “this is going to be a hatchet job on fat”.
    You lose a lot of water in the early stages of any diet, and then Dr Richard Mackenzie says to Xand “You’ve lost 2kg of muscle mass and that isn’t so healthy.” I’m thinking that doesn’t sound right.
    Anyway when I’m at work the next day my colleagues are telling me how excellent the program is and “have I watched it”. I tell them there are things that are misleading (putting it mildly).
    There lies the rub, unfortunately most people rely on programs like this to be well informed and they end up being misinformed. The BBC have got to take part of the blame for the state of our nations health showing programs like this.
    Anyway thanks again Zoë for your time dealing with this. I will point my colleagues in your direction, so they can see that it was a truly poor piece of program making.

  • I’m interested in this statement:

    “It’s food manufacturers who have worked out that the sucrose/fat combo is irresistible, moreish and fattening – to rats or humans. That’s why fake food needs to be avoided.”

    So is eating carbs and fat together worse than just carbs without fat?

    The blood sugar/insulin story provides a strong causal link between eating carbs and getting fat and ill. Could you explain how fat exacerbates the problem?

    • Hi Matthew
      I have advised keeping carbs and fats separate since my first publication (Why do you overeat? When all you want is to be slim) in 2004 for the following reasons:
      1) Because carbs and fat rarely occur together in real foods (avocado being the only sucrose/fat combo and nuts/seeds being the rare foods that have all 3 macronutrients in good measure). Nature tends to provide carb proteins (things from the trees and the ground) and fat proteins (things from ‘faces’) and hence we have evolved to consume carb/protein separately to fat/protein and natural eating would thus be well advised to follow this natural rule.

      2) I concluded that it would be a good idea to separate carbs and fats for weight loss based on knowledge about how the body uses different macronutrients for fuel. The body will always favour carbs for easy glucose. Hence, if any carbs are available, the body will use these for fuel and will look to store dietary fat for later on. The body needs insulin to store dietary fat and it will have insulin if carbs are available. Hence eating steak (fat/protein) with potatoes (carb/protein) creates the perfect fat storing circumstances for the body. Not good for weight loss!

      If the person instead has a baked potato with veggie (bean) chilli – they have carbs/glucose to use for energy and virtually no fat to store for later on. The body will clear some glucose into glycogen; use some glucose straight away and then likely call back upon the glycogen if enough time is left between meals (I also do NOT favour grazing!)

      If the person has steak with salad – the carb intake is negligible and the body can use dietary fat for fuel. Insulin impact is also negligible and thus there is no fat storage scenario for the body and the body happily fuels on fat.

      People following The Harcombe Diet know this as the ‘no mixing’ rule and it seems to work well!
      Hope this is of interest
      Best wishes – Zoe

  • A brilliant well argued response. I also can no longer watch these programmes or even talk to people about them as I get too angry, and don’t want to be producing all that nasty cortisol!!! I will quietly point them to this article instead. Three years ago this month I started Harcombe and it has changed my life forever.

    Thank you Zoe

    Lucy Piper

  • Excellent response to a very dangerous and misleading programme,considering these people were medically trained professionals?.As regards the BBC it has not been balanced for some considerable time.I hope I live long enough to rejoice the ending of the TAX on all, that is the licence fee.

  • I resemble your suggestion that the BBC is “not balanced”. On the contrary, as I see it the BBC always balances the interests of the rich very scrupulously against the interests of the powerful.

  • Bravo, Zoe! I no longer watch these shows as they make my blood pressure go up! I read you and Dr.Briffa instead!

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