I was so excited as I read the headlines on Tuesday’s Daily Mail website (not something that I say too often). ‘One twin gave up sugar, the other gave up fat. Their experiment could change YOUR life’. “This is it!” I thought “This is the turning point!” and I enthusiastically began reading with my heart in my mouth (yes I really do get that excited about these sorts of things). However, the article (a preview of the BBC Horizon programme) was a complete let-down and so I watched the programme last night with a heavy heart knowing what was in store.
Before I start I just want to make a quick comment about the quality of documentary programmes on the BBC – or lack of it. To say that they resemble documentaries better suited to an early secondary school audience is rather demeaning to the children. Everything is filmed to show exactly what the presenter is talking about – just in case we can’t quite understand. Talking about eating fat and sugar? Let’s set up a camera in his kitchen to show him shovelling sugar and cream in his mouth. People like a particular flavour of doughnut? Let’s waste several minutes showing the presenters offering doughnuts to random people in the street. Craving for carbohydrates? Let’s show a close-up of him almost putting a chip in his mouth and then stopping. It’s as if we can’t understand things without them being literally demonstrated by the presenter/’actor’ on the screen. I remember Horizon as being a serious science programme. What has happened? Anyway, rant over…
Right, let’s get to it. The programme (watch here while still available) was presented by two chirpy and camera-friendly twin doctors, Alexander and Chris van Tulleken, one a specialist in infectious disease and the other a specialist in Tropical medicine. They did admit that despite being doctors, they knew nothing of ‘eating healthily’ and that nutrition ‘fell between the cracks’ at medical school. I thought it was quite refreshing to hear doctors admit that.
The battle lines were drawn. The experiment would find out ‘which is worse’ with the anti-fat brigade amassing on UK shores and the ‘sugar is toxic’ brigade over the pond. The doctors agreed to go on ‘extreme diets’ in order to settle the debate once and for all and prevent all-out war. They could eat as much as they want and the idea was to look at the effect of these diets on weight and ‘lifestyle diseases.’ It was quite interesting that they set up the ‘battle’ as American vs. UK opinion.
The high-fat diet consisted of cheese, meat, steak and burgers. There was confusion here because in both the article and the programme, they mention ‘no carbohydrates’ and then go on to talk about low-carbohydrates. Nutritionist Amanda Ursell (more about Amanda’s advice later) talks about minimal carbohydrates but the proportions are never made clear. I would have liked to see the fat/protein/carbohydrate ratio explained just for the sake of clarity. It looks like Alex was on a ketogenic diet (rather than a Paleo-ish high fat diet) but even with a ketogenic diet we would possibly go as high as 50g of carbs a day, so I can’t quite figure if they cut ALL carbs out or whether they just didn’t film him eating the minimal amount of carbs permitted while still remaining in ketosis. Alex worries that he is going to be ‘craving fresh greens’ so I assume that no veg was allowed at all. In addition to this, there was no mention of a period of ‘keto-adaptation’ before the body transitions fully to a fat-burning state. Alex also bemoaned the fact that he would suffer from bad breath and constipation, subjects that were brushed under the carpet for the rest of the programme.
The twins then hop over to Richard Mackenzie at University of Westminster for some tests before embarking on the diets. Dr Mackenzie informs us that ‘High amounts of cholesterol blocks our arteries’ and annoyingly does not differentiate between types. He measures the twins’ body fat percentage which is at 26.7% for Alex and 22% for Chris.
Two weeks into the diet, there is an inane experiment to test their mental agility, in which the twins are given $100,000 to trade with on the stock exchange in the hope of making more cash (with a wonderful cameo by ‘JJ’ who berates Alex for his negativity before the task begins). This test was intercut with Professor of Psychology Robin Kanarek’s grave comments about glucose being ‘the primary and best fuel for the brain’ without which it ‘doesn’t function properly’. I would have liked to see their performance pre-diets and then a comparison made, but never mind. I would also have liked to see any other factors that may have influenced either of the twins, such as caffeine intake, sleep, time difference (as they were on opposite sides of the Atlantic). We were assured that ‘ketones aren’t as efficient as sugars’ and Professor Kanarek very carefully worded the following statement: ‘At least on a short-term basis (my italics), a high carbohydrate diet will facilitate memory.’
Anyway, back to the trading floor with shots of high-fat Chris sighing and burying his head in his hands as his finances went into meltdown. Triumphant, sugary Alex announces that ‘I’ve absolutely thrashed him’ and we are told that Alex has made only $300 while Chris a whopping $800. Chris announces that ‘a big carb breakfast helped me do that.’ Really?! I make that 0.5% difference of the starting value, not really enough to sell me one fuel over another, but let’s not be picky…
We then have an interview with Robert Lustig, Professor of Clinical Pediatrics at the University of California, San Francisco and presenter of Sugar:the bitter truth. Professor Lustig explains about how the liver turns excess fructose into fat and how glucose activates insulin. This is followed by Alex stating that reports on high sugar diets use ‘unrealistic amounts of sugar to prove their point’ and he announces his scepticism. Move along please, nothing to see here…
The twins then pop in to see nutritionist Amanda Ursell to see if eating fat and sugar have different effects on how hungry we get. As we expect, the high fat diet leaves Alex feeling fuller for longer while Chris eats around an extra 30% of food and admits that ‘calories do not necessarily make you feel full and I was hungrier quicker.’ Does this signal a move away from the calories are calories are calories thesis? No, not quite as the twins explain that ‘as sugar is an easy source of calories, you get fatter quicker.’ Back to calories then…
Then we moved on to fats. We are told that the recommended saturated fat intake is no more than 30g while quickly slipping in a fleeting comment about this being ‘currently contested’. Things are moved very swiftly on to trans-fats and how bad they are. There is no attempt to examine the argument in favour of saturated fats, although they can spend precious minutes of the documentary handing out doughnuts to people in the street. We are just told that fat has twice as many calories as sugar (back to calories again) and we are informed that our body ‘turns dietary fat into body fat easier than it turns sugar into body fat.’ That’s fat sorted then…
We then saw the twins taking a gruelling test riding a bike up a mountain, alongside a ‘commercial’ for porridge from the helpful Tour de France man. He also tells us that Alex is in ‘the last state that we want our athletes to be in.’ Alex announces that he ‘hasn’t eaten carbs for weeks.’ I remind myself that this is all about extremes…
A return visit to a worried looking Dr Mackenzie confirms that sugary Chris has lost 1kg – 0.5kg of fat and 0.5kg of muscle. Alex has lost 4kg – 1.5kg of fat and 2kg of muscle (where did the other 0.5 kg go?!). Proportionally, they have lost the same amount of muscle (50% of the total loss). The doctor informs us that people who lose muscle mass are ‘more likely to visit the hospital and be ill.’ However, presumably people who are very overweight are even more likely to visit the hospital and be ill, so it makes sense to get the fat off with a very effective high fat, low-carb diet and later exercise to build muscle if they can. I don’t remember seeing headlines about the amount of people turning up at the hospital with diseases due to lost muscle mass, but there is an awful lot about the effects of diseases due to obesity. Maybe I’m missing something.
There is also a quick examination of their cholesterol which has stayed normal in both twins (no mention about what type of cholesterol here, or any measurements of tryglycerides). On to announce that Alex has a raised blood glucose from 5.1 to 5.9 which is apparently ‘pre-diabetic’ although I keep turning up results on the internet that suggest this is at the top of the ‘normal’ range. Again, I would have liked to see what their levels were pre-diet as Alex was quite overweight and carrying a lot of extra body fat around the midriff. Chris, who worryingly is becoming ‘better at producing insulin’ in response to all that sugar (oh that’s ok then…), appears to be relieved and oblivious to the fact that another few months on this diet will surely make him insulin resistant and diabetic.
We then go over to Professor Susan Jebb at Oxford University who confidently informs us that a diet ‘which has extreme composition is not the answer’ and that ‘cutting out sugar does not have a big effect.’
We are now into the home run and while Richard (my other half) is losing the will to live I encourage us to battle on to the end. The conclusion is in sight and with the help of some rats and cheesecake we finally get to the advice we have been waiting for all along – avoid processed food. Yes it’s the magic combination of 50/50 fat and sugar in processed food that is making the nation obese. All faddish diets are worrying and misguided, and the enemy is neither fat nor sugar but both together. It’s not the fat that’s the problem (although remember that warning about saturated fats) and it’s not the sugar (as one of the twins explained earlier, we don’t binge on sugar cubes). A final suggestion to cut calories was slipped in for the last time and that was that. Phew!
This programme set out to exonerate a high carbohydrate diet from any blame in the nation’s obesity crisis. It did this by deliberately choosing extreme diets with which to make its point and to hell with any sense of proportion or fairness. Important topics were skimmed over quickly (the debate about saturated fats, the different types of cholesterol, what causes heart disease, the effects of a low-fat, high carbohydrate diet). Subtle (and not so subtle) remarks were made throughout the programme that made it clear that the evidence had been carefully chosen to trash a high-fat, low-carb diet and to ‘protect’ high-carb diets. We are all aware that the hedonic impact of food is mighty important, but there are many people who have spent decades on high-carb, low-fat diets (while simultaneously avoiding hyper-palatable junk food) that have experienced a myriad of problems.
The consensus was a return to the same advice that governments and nutritionists have been trotting out for decades – a ‘healthy’ wholegrain diet, low in saturated fat and processed foods. Don’t worry too much about the sugar as long as its low fat, so stock up on those low-fat, sugary yoghurts because they are fine.
I wanted to have a look at the work of some of the experts that appeared in the programme. This turned up some rather interesting information. Professor Susan Jebb ‘works closely with the Department of Health, Public Health England and National Institute for Clinical Excellence’ and is also the Chair of The Department of Health Public Health Responsibility Deal – see here. They had something to do with that strange swimming pool/saturated fat pledge that I wrote about last year. Professor Jebb works with industry and retailers on such ‘Responsibility Pledges’ and is on a ‘high-level steering group that encompasses health professionals, food industry representatives and civil servants’ – see here. She has also been vocal in warning of ‘fad diets.’ Professor Jebb has previously come under fire for her work with Weight Watchers. Also, check out this article from the excellent Dr Briffa here.
Amanda Ursell is a nutritionist and also a member of the British Dietetic Association. I wrote about the BDA take on ‘fad diets’ here. I was interested in the sort of diet that Amanda recommends and so I hopped over to her website and had a look. For breakfast, Amanda recommends amongst other things apple muesli, French toast, blueberry porridge, fruity toast, peanut butter toast, fresh fruit bowl and bacon sandwiches – and skinny cappuccinos. Plenty of sugar then… I was also interested in her take on the ‘French paradox’, which I always thought was to do with the fact that French people ate lots of saturated fat and yet had lower incidences of heart disease. Saturated fat is mysteriously missing from Amanda’s tips on French eating.
Professor Kanarek has served as ‘a member of the National Academy of Sciences, Committee on Military Nutrition Research, and on review committees for the National Institutes of Health, United States Department of Agriculture, and National Science Foundation’. Professor Kanarek contributed to a similar study on low-carb diets and cognitive function in this paper in 2008 with the USDA Human Nutrition research Centre on Ageing (unfortunately tracking dieters for only 3 weeks). A very low-carbohydrate diet (maximum of 10-16g per day) was compared to the ‘healthy’ diet as recommended by the American Dietetic Association.
All interesting stuff but it did leave me feeling that the scales were heavily weighted towards finding a favourable outcome for conventional wisdom on dietary matters. We were left with many unanswered questions, for instance what is the effect on weight and lifestyle diseases (the original question posed in the documentary) of a long-term high sugar, low-fat diet. I did not feel that this was addressed in any comprehensive way, in fact hardly at all other than Robert Lustig’s brief appearance followed by a sceptical comment from one of the twins.
Listening to people talk the day after the documentary was aired, the consensus seemed to be that all things in moderation and an avoidance of those ‘fad diets’ was the most sensible option. It’s a sad state of affairs.
Ending on a more positive note, my talk on Paleo to the ladies (and gentleman!) at the social club went down extremely well and their enthusiasm and interest cheered me no end. Perhaps things are not that bad after all…
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