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Slimming World’s view of low carb diets

The UK Sun newspaper seems to have been the first to pick up this story: “‘CARBFUSION’ Low-carb diets are ‘damaging the nation’s health’ say Slimming World experts” (Ref 1). It was soon covered by other UK newspapers. Thankfully the nonsense seems to have been contained to this side of the pond. The Daily Mail ran with “Low-carb diets could make you FATTER, say Slimming World experts as they reveal the 13 ways carbs can help you LOSE weight” (Ref 2).

The story emanated from a press release from Slimming World called “How low-carbohydrate diets are ‘damaging the nation’s health’” (Ref 3). I felt that the words “oh, for goodness sake” needed to follow such an ignorant statement. The press release was based on two surveys that had been commissioned by Slimming World. One done by YouGov on a sample of 2,103 adults (representative of the UK population) and one done by Slimming World on 2,481 of their members – both surveys were undertaken in November 2018. The UK wide survey found that 48% of people who have tried a low-carbohydrate diet found it difficult to follow (so 52% didn’t). The main reason for this was that they enjoyed eating carbohydrates too much (52%). Two thirds of respondents (66%) reported that they had heard that low-carbohydrate diets are better for weight loss. When it came to Slimming World members, 97% were pleased that they could enjoy carbs while following Slimming World’s plan. There was nothing terribly startling in any of these findings.

The most interesting part of the media coverage was an article on the health and well-being web site “Healthista” (Ref 4). This article was based on an interview with Dr Jacquie Lavin, nutritionist and Head of Nutrition and Research at Slimming World. The article was called “13 ways carbs can help you lose weight” and it was repeated in the Daily Mail article. Let’s take a look at the 13 claims and see how accurate they are (direct extracts from the article are in black and my – ZH – comments are in red):

“13 ways carbs can help you lose weight”

“1) Carbs fill you up

“At Slimming World, starchy carbohydrates such as pasta, rice, potatoes, cous cous, and quinoa are considered ‘Free Foods’, which you can eat freely to satisfy your appetite.

“‘These foods are bulky and provide fibre which makes them filling and satisfying, especially when eaten with foods containing protein,’ says Lavin.”

ZH – Apparently supermodels eat cotton wool balls to fill themselves up. This would arguably be more effective than freely eating as many starchy carbohydrates as you like to try to feel full. The reason being, that those starchy carbohydrates are all packed with glucose, which will go straight into the blood stream and create havoc with blood glucose levels.

The goal of the successful slimmer should not be to feel full (having a full tummy is simply uncomfortable – there is no evidence that feeling full all the time will aid weight loss. In fact you’re probably eating too much if you feel full all the time). The goal of the successful slimmer should be to achieve stable blood glucose levels (the same goes for the person aiming to avoid type 2 diabetes). When blood glucose levels are normal and stable, any physiological driver to eat is substantially reduced. The best way to achieve and maintain stable blood glucose levels is to eat fat/protein foods (meat, fish, eggs and dairy) and not carb/protein foods (grains, fruits, legumes etc).

“2) Carbs keep you regular

“Fact: Brits don’t get enough fibre and this can lead to sluggishness and constipation leaving us uncomfortable and bloated – not good for weight loss or our health.”

ZH – What goes in must come out. If you put more carbs in, then more carbs need to come out. That may be your idea of a good thing, but it’s not mine. Fibre seems to be the only waste product that is considered good. Waste in all other walks of life is, well, waste!

Brits allegedly don’t get enough fibre relative to a random fibre target made up by the government, working hand-in-hand with fibre providers a.k.a. cereal companies. Constipation should be defined as discomfort in passing stools, not as not doing a number two several times a day. If you’re not producing much waste and you feel comfortable getting rid of the waste that you do have, you’re eating efficiently.

“3) Carbs are full of nutrients

“‘If you are really restricting or have completely cut out carbs you are at risk of missing out on a lot of important vitamins, minerals and especially fibre,’ says Lavin.”

ZH – do you see how fibre has been used as a rationale for the first three points already? The most important thing to say about carbohydrate is that we don’t need to consume it. But then an article raving about carbohydrate is not going to include that vital fact. I constantly see fibre being used as the rationalisation for why we should eat carbs, but carbs are not essential and so fibre is not essential – that is an inescapable fact combined with inescapable logic.

Because carbohydrates are not essential for human to consume, it cannot be the case that we need to consume carbohydrates for any micronutrients (vitamins and minerals). Carbohydrates can provide vitamins and minerals, but you will always be able to find a fat/protein (usually animal) food that provides more.

I present the evidence for this point in the table below. The table includes calories, essential fats, protein quality (note that only the animal products score over 100), vitamins and minerals. The values are all presented for 100g of product. The ‘winner’ in each row is highlighted (in bold), so rice wins on calories (not sure that’s one you want to win). Oily fish wins on essential fats (and in an ideal omega-6/omega-3 ratio). Liver wins for most vitamins. Cocoa powder wins for most minerals (you’d be better off enjoying very high cocoa content dark chocolate than starchy carbs). Where pasta or rice did do well, I’ve added a note to show that a fat/protein food would still beat the starchy carb hands down.

(All per 100g of product)
(Refs 5-10 for food items)

Chicken Liver



Whole wheat pasta

Brown rice

Cocoa powder








Omega 3 (mg)







Omega 6 (mg)







Protein Quality (100+ = complete protein)







Vitamins (RDA)

A Retinol (900 mcg)







B1 (1.2 mg) Note 1







B2 (1.3 mg)







B3 (16 mg)







B5 (5 mg)







B6 (1.7 mg)







Folate (400 mcg)







B12 (2.4 mcg)







C (90 mg) Note 2







D (15mcg)







E (15 mg) Note 3







K (120 mcg)







Minerals (M)

Calcium (1,000 mg)







Magnesium (420 mg)







Phosphorus (700 mg)







Minerals (T)

Copper (0.9 mg)







Iron (18 mg)







Manganese (2.3 mg)







Selenium (55 mcg) Note 4







Zinc (11 mg)








Note 1 – pick sunflower seeds to win this one – 1.5mg of vitamin B1 per 100g (Ref 11).
Note 2 – did you know that liver has four times the vitamin C of apple?
Note 3 – sunflower seeds are unbeatable for this one – 33mg vitamin E per 100g.
Note 4 – pick Brazil nuts to win this one – 1,917mcg selenium per 100g (Ref 12).

Put simply – no starchy carbohydrate will win any nutritional contest, ever.

“4) Carbs help you keep weight off

“People might initially lose weight on low-carb regimes but may not manage to keep the weight off long-term because cutting out carbs isn’t sustainable in everyday life, Lavin asserts.”

ZH – notice how “low-carb regimes” have become “cutting out carbs.” Cutting out carbs entirely is sustainable – it is being done by an increasing number of people (e.g. Mikhaila Peterson, Dr Georgia Ede, Dr Shawn Baker). It’s not my idea of fun and it’s not necessary for most people. However, in my 15+ year experience of helping people to lose weight, it is far easier to cut back on carbs than it is to eat them completely freely, as Slimming World recommends. To lose weight and to keep it off long term, my top tip would be to stop eating junk and Slimming World actively encourages daily consumption of junk with the Syns allowance.

“5) Carbs fuel your workout

“Your body’s preferred fuel source is glucose and while it can make this from protein and fat, it most quickly and efficiently gets it from carbohydrates.”

ZH – I agree with this, but it’s why you shouldn’t eat carbohydrates before a work out if you want to lose weight. If you eat carbs before a workout, Lavin is right – your body will use the carbs you’ve eaten for fuel. If the aim of your workout is to lose weight then i) don’t eat carbs beforehand and ii) don’t have carbs stored (i.e. consume a low-carb diet in general) and then your body will be forced to look for fat for fuel. If you haven’t recently eaten fatty acids, your body will need to break down body fat for fuel. Your workout will be more effort, but you wanted to lose weight, yes?

“6) Your brain loves carbs

“‘Your body can use ketones but it’s not an optimum fuel source, especially for the brain, which needs glucose to function at its highest level,’ says Lavin.”

ZH – there are a few points to make here:

i) Parts of the brain need glucose, parts are happier with ketones (and certain conditions, e.g. epilepsy, can be transformed with ketone, rather than glucose, dominant fuelling) (Ref 13). The body has evolved to use both glucose and ketones and thus it makes sense to continue to facilitate the working of both mechanisms. Advising people to consume starchy carbohydrates ad lib will shut off the ketone option ongoing.

ii) Just because parts of the brain need glucose doesn’t mean that we need to consume it. The body can make glucose (the process is called gluconeogenesis). Dr Eric Westman does a brilliant lecture on the requirement for carbohydrate (none). He notes that the brain may need 120g of glucose a day, but that doesn’t mean that we need to consume it. 80% of the central nervous system energy can be derived from ketones, leaving about 20-28g of glucose a day that is really required by the brain. Guess what carb intake is advised for people on a very low carbohydrate diet? About 20-30g a day (Ref 14).

iii) Even if we consumed 120g of carbohydrate a day, that would still be a moderately low carbohydrate diet. I dread to think how much carbohydrate could be amassed following this advice: “pasta, rice, potatoes, cous cous, and quinoa are considered ‘Free Foods.’”

“7) Carbs are actually quite low calorie

“Imagine a portion of cooked pasta – 200 grams worth. It only contains 260 calories while still being filling and containing zero fat. Even with 100 grams of lean bolognaise sauce on top (190 calories) that would amount to 450 calories.

“Now imagine steak pie, 200 grams worth. This contains a staggering 679 calories and 48 grams of fat and the chances are you still want to eat your potatoes with it.”

ZH – Steak PIE is still carbohydrate, duh! And I thought potatoes were free. Take a look back at the table above. Which were the highest calorie foods in the table? The brown rice and the whole wheat pasta. And they weren’t even the most nutrient dense for all those calories. If you compared sardines with brown rice per 100 calories, for example, the brown rice would look almost twice as bad as it does in a 100g vs. 100g comparison.

If you really want to compare carbs vs non-carbs, then you need to look at a fat/protein based meal (as we call them on The Harcombe Diet). Here is such an example – also approximately 450 calories – absolutely delicious, packed with nutrients and this would keep you satiated and with stable blood glucose from dinner until breakfast (Ref 15).

“8) If you limit your sugar, it’s easier

“Sugar (added or ‘free’ sugars) is classed as a carbohydrate, but it’s not going to help your weight loss – it will hinder it. ‘Sugar can provide a lot of calories without any beneficial nutrition, so you’re not getting many (if any) vitamins and minerals with sugary foods,’ says Lavin.

“It can also lead to a sharp spike in blood sugar levels and a subsequent crash which can lead to more cravings and weight gain”…

“You can choose 15 Syns a day, depending on your weight and goals – a Curly Wurly contains 6 Syns and a small bar of Green & Blacks has around 4 Syns.”

ZH – carbs are sugar! I agree that added sugar (sucrose) is not going to help weight (or health) and that it is completely empty calories. However all carbohydrates are, or break down into, sugar (Ref 16). Lavin says sugar can “lead to a sharp spike in blood sugar levels and a subsequent crash which can lead to more cravings and weight gain.” I entirely agree. Replace the word sugar with carbohydrates – especially starchy carbohydrates – and the sentence still holds.

As for those Syns, our American friends are fortunate not to know what a Curly Wurly is. It’s a concoction of mostly sugar, vegetable fats and chemicals and it truly is a sin, in the proper meaning of the word. It certainly has no place in a healthy diet (Ref 17).

“9) Go easy on dry carbs, they can de-rail the diet

“Bread is one carb that should be eaten in a measured amounts (sic) at Slimming World, and not eaten freely like other starchy carbs such as pasta, potatoes and rice. ‘Bread doesn’t contain the same amount of water as other carbohydrates (see below), and so it’s not as filling,’ says Lavin.”

ZH – This one baffled me at first. Why can’t Slimming World people just eat bread with a glass of water? Quinoa, millet, buckwheat, wholemeal rice and pasta (see below) all start off dry and then water is added to make them digestible. If carbs can be eaten freely because of water, then why not add/drink water?

Then I worked out what the real principle is – Slimming World doesn’t want you eating starchy carbohydrates that you don’t have to cook first. Why? Because you’ll overeat them, no doubt. The same would go for pasta, rice and potatoes if you were at an all you could eat buffet, no doubt. I do accept that someone would be far less likely to finish their dinner and then decide they want more pasta/rice/potatoes and then go to the trouble of cooking more. Even the most ardent food addict wouldn’t do that – they’d reach for the bread, or cereal, or readily available carbs.

This is not a bad principle, therefore. Far better to cook meat/fish/eggs/cheese and vegetables for your dinner than starchy carbs, but the principle of preparing food, rather than eating prepared food is a good one. The water thing is a red herring though.

“10) Fill up on high water, high fibre carbs

“Grains such as quinoa, millet and buckwheat, wholemeal rice and pasta as well as root vegetables such as potatoes and sweet potatoes are all not only a source of fibre, they’re also high in water (either naturally or because they’re cooked in water).

“‘Foods like pasta or rice absorb water when they’re cooked which can make them much more filling than drier carbohydrates, while still delivering the same amount or even higher amounts of nutrients and fibre,’ says Lavin.”

ZH – As above – the water is a red herring. If water fills you up, then drink it. Fibre gets three more plugs, because that’s the way to rationalise carb consumption in a world where carbs are non-essential.

“11) Control high risk foods (but don’t ban them)

“Thanks to the Syns system, you could have a small glass of wine (5 Syns) and a small chocolate bar (4 Syns) or a bag of Walker’s crisps (6.5 Syns) each day and still fall within your 15 Syn limit.”

“‘Before long, that control you’re practicing – the small daily treats – become a new habit instead of your previous binges’.”

ZH – Slimming World people are higher beings than me because I find it a thousand times easier not to eat junk confectionery than to try to eat a small bar of junk confectionery every day. I always compare this advice to that which we give alcoholics – i.e. people addicted to alcohol. We don’t tell alcoholics just to have a small glass of wine or beer a day – and “then you’re having a daily treat, not your previous binge.” This advice denies the existence of sugar/carb addiction (I have never met anyone addicted to lamb or salmon) and it’s bad and dangerous advice in my experience.

“12) Control your fat

“For example, 14 cashews would be 6 Syns. Likewise, you can still have your butter or cream, but portioned out – a teaspoon of butter is 2 Syns. This also means trimming visible fat off meat, going for mince that is less than five per cent fat and not eating the chicken skin too.”

ZH – When I see the words “avoid fat” or “limit fat”, I feel like adding the words “soluble vitamins”, because this is concomitantly advice to avoid/limit fat soluble vitamins.

Having said this, I actually agree with this advice, in the context of the overall Slimming World regime, but for one reason only – because you’ll be eating such a humungous amount of carbohydrate! Just as I advise people not to eat fat liberally unless they first go very low in carbohydrate, so you should not eat carbohydrate liberally unless you go very low in fat. This very high carbohydrate, very low fat diet is exactly what Public Health England wants people to eat, as I showed in this post (Ref 18). It is an unbalanced, unnatural and nutrient-deficient diet, which is at least associated with type 2 diabetes and obesity. You will be deficient in fat soluble vitamins and probably essentially fatty acids, but, hey ho, you can eat your appetite’s delight in pasta, so who cares?!

“13) It’s all in the cooking

“‘If you’re baking your potato, that’s fine,’ says Lavin. ‘Obviously cooking chips in lots of fat isn’t helpful for weight loss, but there is a healthier way to make chips – you cut them into chips, parboil them and put them in the oven with some oil spray. If you leave the skin on the potatoes, you will be getting extra fibre too’.”

ZH – as above – I agree with watching fat if you’re consuming carbohydrates ad lib, but then I would never advise someone to consume starchy carbohydrates ad lib. Did you spot fibre again? It gets 9 mentions in the full 13 point article.


None of these 13 points provides any evidence for how carbs can help you to lose weight – certainly not relative to consuming far more nutrient-dense, satiating and blood glucose stabilising meat, fish, eggs, dairy and non-starchy vegetables. “Consume foods that require cooking” would have been a good tip, but, again, meat, fish, eggs and non-starchy vegetables would be better foods to cook for weight and health.

My book The Diet Fix came out at the end of December (2018) and I managed to boil the eating advice down to two principles:

1) Eat real food;

2) Choose that real food for the nutrients it provides.

As you can see from the evidence presented above, if you do this, you will base your meals on meat, fish, eggs, dairy, non-starchy vegetables (and very dark chocolate) You can also enjoy porridge, brown rice and baked potatoes (as I do), but it should be with the knowledge that you could have chosen something more nutritious and that starchy foods should not be your staples at most meals.

The advice to consume starchy foods ad lib and junk (Syns) every day is a recipe for repeat slimming business in my opinion.

Ref 1:
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Ref 14:
Ref 15: Approximately 250g of steak ( and a selection of non-starchy vegetables.
Ref 16:
Ref 17: Glucose syrup, sugar, palm oil, skimmed MILK powder, cocoa butter, cocoa mass, whey permeate powder (from MILK), MILK fat, emulsifiers (E471, sunflower lecithin, E442, E476), salt, flavourings, sodium hydrogen carbonate.
Ref 18:

13 thoughts on “Slimming World’s view of low carb diets

  • Goodness me what a rant against SlimmingWorld! I’ve been following their plan for 9 months now and have lost 26lbs. Feel absolutely great & find it a really easy diet to follow. Never going back to the high carb, high sugar, full fat everything I was on before. It’s the best diet plan by far-no calorie counting just free food plus a few Syns each day.

  • Hi Zoe.

    Thank you for doing the research and answering questions that many people do not have time to do. I appreciate you and the work you do. I also loved your talk on fibre at ‘low carb down under’.

    All the best, Lewis

    • Hi Lewis
      Many thanks for taking the trouble to write such a lovely comment – really appreciated.
      Best wishes – Zoe

  • When I read “fibre” I find it helps to replace it with “profit” – it used to be a waste product from flour refining then they put a “healthy” label on it and marked the price up.

    Mind you it is probably a good thing to add to a high carb diet as it will slow the glucose and insulin spikes from all the “dense acellular carbohydrate”.

    On a low carb diet, not so much. Eating meat, poultry, game, fish and a wide range of vegetables plus grass-fed butter, cheese, 85% chocolate etc. my bowels are as regular as an atomic clock. This was never the case when I ate wheat, Also I seldom fart and no longer have GERD.

    IMO this is all part of the fight back since so many people are improving their health when they aren’t meant to. Something I only discovered recently, Jimmy Wales is on the board of the Guardian – that probably explains what is happening on Wikipedia. Vegans/Seventh Day Adventists/cereal processors now control the dialogue in most of the mainstream media especially the Guardian, and now Wikipedia too.

  • Great write up Zoe!

    Slimming World provide yet another crazy non evidence based rave about carbohydrates and the benefits of fibre!

    Sure, the benefits of fibre are good, but not from grain-based foods. I run a low carb meal planning service for people with type 2 diabetes (not keto but low carb) and we include TONS of vegetables in our plans, not to mention nuts and seeds, etc, which in case these dieticians don’t realise, contain more fibre than high carb grains – and obviously more nutrients! Our members are losing weight, lowering blood sugar, blood pressure, cholesterol, and improving their health on every level – by eating real food. Like you say Zoe, the principles are pretty simple.

    I’m sure you’ve seen this recent ‘landmark study’ news blast on fibre Zoe – – might make a good review for you to dig into.

    Love your work – thanks!

    • “…a good review for you to dig into” copy that! As usual in the Lancet abstract this article mentions there are no references to the rct’s -never trust those confounded cohort studies!- so I can’t analyse it myself without paying for the fulltext article.
      I googled “rct dietary fibre” and found 2 rct’s which concluded no effect on CHD markers cholesterol and blood pressure respectively. Anyway, even if there are dozens of rct’s that do and these are the exceptions, they are not about keto. And there are numerous keto rct’s showing spectacular improvements in all these CHD markers!

  • I checked out the Grauniad (showing my age, too!) article Hugh mentions, above, and found that on 10 January, it posted this:

    Apparently the landmark study, published in the Lancet on 10 January, was commissioned by the WHO and others and it will now inform WHO guidelines.

    Along the side of the article are these links:

    Information like this could explain why my Guardian-reading mates appear to think I have a death wish…..

  • Thanks for demolishing this “profit focussed diet industry carbs are good” nonsense so efficiently.

  • Hi Zoe,
    I am so pleased you did this rebuttle to what can only be described as a ‘slimming world war cry’ to get everyone on board with slimming world because the alternative is going kill you!
    Glory seeking, headline grabbing nonsense. But what is sad, is that it is only the headline that is read. Not many people will read the article and think what a ‘lot of tosh’ . I shall share as much as I can.

  • I had to Google Curly Wurly… and now I wish I hadn’t. That’s horrible.

    Today’s Grauniad has yet another anti-keto screed (which seems mostly to be a subdued promotion for a new book). It contains the following gem:

    “Being low in fibre, high in saturated fat and red meat, and extremely restrictive, the keto diet does not really align with nutritional guidelines issued by government experts. The diet’s critics say it is, at best, a passing trend and, at worst, a socially acceptable form of disordered eating. ”

    I find it most amusing that low-carb/keto are “extremely restrictive” while veganism (which is at least as restrictive) is hailed as a way to save the planet.

    I’m not sure where they get the “low on evidence” thing — there have been dozens, if not hundreds, of studies of varying degree of low-carb diets. It’s the government guidelines that are lacking in evidence, if anything.

    Link to article:

    • Hi Hugh
      The Grauniad (ha ha – not everyone knows why it is called that!) is all over the place. I’m totally with you on the insanity of vegan is good (4 out of 9 food groups avoided) and low carb is bad (which tends to avoid grains only and pick carefully from a couple of the other 9)

      Rolls eyes!
      Bye for now – Zoe

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