Under the encouraging headline “Doughnuts are not the enemy”, the Daily Mail discusses some interesting new research on diet, carbohydrates and Body Mass Index (BMI). However, they also quote Patrick Holford as an expert: disappointingly, Holford’s claim that high carbohydrate diets lead to fat gain is based only on research in animals. The Mail also fails to mention Holford’s competing interests in this area (although they do mention another professor’s funding source when discussing his academic research).
The Mail article is about some interesting new research by Prof Gaesser – looking at “Carbohydrate Quantity and Quality in Relation to Body Mass Index”. Gaesser’s review of the evidence finds that “Because overall dietary quality tends to be higher for high-carbohydrate diets, a low-fat dietary strategy with emphasis on fiber-rich carbohydrates, particularly cereal fiber, may be beneficial for health and weight control.” In other words, a ‘normal’ balanced diet may be beneficial for health and weight control (the Mail’s headline is, sadly, a bit too optimistic: Gaesser found that “Data on the association between glycemic index and BMI are not as consistent” and, at any rate, good quality doughnuts are deep fried).
There are, I’m sure, many sensible criticisms that could be made of Gaesser’s review – but Holford does not appear to come up with any. Instead, Holford argues that “animal studies had shown high-carbohydrate diets “convert rapidly into fat””. I can see how such studies are interesting, but there is a major flaw when extrapolating from such studies to humans: lab animals generally eat what they’re given; humans, on the other hand, have rather more freedom in this regard.
In terms of weight management, this can be a problem: for example, when Gaesser analyses intervention studies aimed at weight reduction (p. 1773) he finds that they lead to “a relatively small degree of weight loss”. Although such losses – about 1-4kg – were large enough to be meaningful, one would have expected more weight loss if the subjects had been eating an ‘optimal’ amount of food (be it high- or low-carb) and burning an ‘optimal’ number of Calories through exercise. By focusing on animal studies, Holford thus rather misses the point – getting people to eat little enough food and do enough exercise that they lose an ‘optimal’ amount of weight (and then keep it off) is often a more substantial challenge than deciding whether high- or low-carb diets would be ideal. Embarrassingly, Holford is Professor at Teesside University – where they have a really excellent Centre for Food, Physical Activity and Obesity. One wonders why the Mail did not speak to some of Holford’s colleagues at Teesside – those with real expertise in this area – if they were seeking informed opinions on diet and BMI.
My other concern is that Holford is simply described as a “British nutritionist”. Aside from the fact that ‘nutritionist’ is not a protected title in the UK – anyone can call themselves one – it seems rather unfair that the Mail does not declare Holford’s competing interests in this area. They do state that Prof Gaesser’s “work is partfunded by the baking industry”, but don’t mention that Holford also has competing interests in promoting low glycaemic load diets: for example, Holford has written/co-authored numerous low-GL diet related books, and Health Products for life sells “an alternative natural sweetener that tastes just like sugar but has 40 per cent fewer calories, an extraordinarily low glycaemic index”.
So, one feels rather sorry for Prof Gaesser. He produces a decent quality review article, which the Mail then reports under a misleading headline. The Mail rather pointedly brings up the funding source for (some of) Gaesser’s research, but fails to mention Holford’s competing interests. The Mail also faithfully reproduces Holford’s rather spurious criticism of Gaesser’s work, entirely unchallenged.
In fact, I feel so sad about this that I think I’ll need to go eat that doughnut…