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Cambridge University Science Magazine
The post-truth era has taken over - beliefs are emphasised while cold hard facts are ignored. From Kellyanne Conway’s insistence that falsehoods were "alternative facts", to Nigel Farage's flip-flopping on the promised £350m for the NHS, nothing seems to be untouched by the post-truth haze. But perhaps all this is not so very new. We have seen questionable 'facts' before, often with a hefty sprinkling of pseudoscience on top. The shining spearhead of pseudoscience is perhaps the fad diets industry, which claims to serve up a trim waistline on a silver platter. Unfortunately, the holy grail of weight loss with minimal the effort is just that, an age-old myth. The renowned Cambridge academic, Dr Giles Yeo, recently appeared in an episode of the BBC's Horizon entitled "Clean Eating the Dirty Truth". In the program, he tore down some of the fad diets plaguing the nutrition industry. Bluesci asked for his thoughts on the post-truth era of diets and how we can control what we put into our mouths.

Dr. Yeo believes that people’s attraction to pseudoscience over 'experts' is two-fold. "[First], science, in trying to determine if something works or not, takes a long time. [However], people are impatient, particularly in situations where they need a quick answer. The second thing is that scientists always argue with each other [and we] always change our minds. We’re paid to argue with each other as scientists, and we change our minds [when] data emerges to prove or modify our previous hypothesis. It’s [then] our duty to change our minds."

The trouble with fad diets, he says, is that they instead "mine something out of a kernel of truth and then run with it. Because they provide a clean, crisp, and pretty answer, people prefer to listen to them. Ultimately - because losing weight and controlling your diet is inherently difficult - [it] is therefore particularly amenable to easy answers. Our biology makes it difficult to lose weight, because we’ve always evolved through a time where there's been too little food, only now there is too much food. Therefore, any time [our] body starts losing weight, [our] brains are programmed to prevent it. On top of that, there is also a variation in terms of how hard [our] brains fight [weight loss]."

Dr Yeo's research is focused on the genetic causes of obesity, but he believes that the environment we find ourselves in also plays a large role. "The problem is, obesity and diet-related illness [...] is a product of the changing environment. The variation in why some people get fatter than others, that's genetic, but the drive of the increase in body weight is the environment. The big problem is, if we don’t change the environment, we are not going to fix the problem. Now there are going to be, to differing levels, pharmaceutical, surgical, and other interventions, [but] are we really expecting to give all the people suffering from overnutrition drugs to cure their disease? I just don't think so. That's the pessimistic view; I am an optimistic person at heart."

When speaking of environment, Dr. Yeo defines it "in its broadest context, not only in terms of physical activity or our food environment. Even if you look at socio-economic class, that influences the type of foods you may get. It is going to be difficult to change the environment— and more crucially, the solution is going to be different for different people. That is the problem [of] a lot of dietary advice [where] it tends to be 'one size fits all'. The general physics of it [is the same of everyone] - if you eat less and move more, you'll lose weight; however, the way you achieve that is layered and mired in complexity. Some people are more psychologically responsive to [focussing] on [a] diet two days a week, the rest of the five days [eating] what [they] want. Some people would prefer to lower [their] carbs and increase the numbers of proteins, but do it every single day. [Some] people respond to stress by eating, and some people respond to stress by stopping eating — it’s bimodal. We know the phenotypes, and [there is] a genetic basis for it. We need to be able to understand how each of us is going to respond to these environmental changes. Then, by some evidence-based method, put together some kind of [weight loss] strategy."

Oran Maguire

Dr Yeo also gives his opinion on the food industry: “[There are] a lot of people who blame the big companies - McDonalds, Nestlé, Unilever - but they're not out to make us fat, they're there to make money, and we have to interact with them. If we don't interact with the people who make our food, how are we going to solve the problem? I think, in my perhaps naïve 'Shangri-La' view of things, the companies might realise that if they give us healthy food we’ll stay alive longer [to] spend more money with that company. At the end of the day, the most effective way to change the environment is if the market forces make them change.”

Though he is optimistic that market forces can cause a shift in the larger food environment, the realities of the current environment still look grim. Dr Yeo clarifies the idea of food addiction and outlines some of the ways the environment manipulates the psyche to encourage consumerism. “Food addiction does not exist chemically. [However], there are situations in which specific behaviours hijack some of the addictive pathways. [You can eat] for reasons which have very little to do with hunger, and that’s what I call the "oooh" factor, which are hedonic pathways that makes you [eat] more. I think you can get addicted to the actual eating behaviour. Nonetheless, [food companies are trying to hijack those addictive pathways, those hedonic pathways, to make us buy more [with] for example something called the incidental virtuous food. Cereal, for example, always has strawberries on the [box]. The strawberries act as an incidental virtuous food, so [consumers think] this is healthy cereal, it's got strawberries in it, so therefore I'm going to have more of it. Supermarkets are another trick. Most people tend to go around the ends [of the aisles] quickly and slow down as they get to the middle of the aisle. So the stuff on the edges of the aisles are all on sale to make you stop, and the stuff in the middle of the aisles at eye level are never on sale. That tends to be where the most expensive stuff sits. Imagine if only broccoli was put [in the middle of the aisles]. [One] can shift people [into] buying things one way versus the other.”

Dr Yeo says the information that he has gathered over the years has yet to be concisely put together into a book. "There are books out there which sell specific diets, but is there a book out there which actually brings together all the information? I don’t think it exists." In terms of educating the public, he believes that "education in the most [basic] sense is not going to help because people already know what they need to do to lose weight. We need to show people how to eat less, rather than tell them to eat less, but it's going to take time, and we're going to argue with each other, [meanwhile] people are going to turn to fad diets. Pessimistic hat on again."

Banner image credit: Michael Stern