An article in New York magazine some years ago throws light on the complex relationship between scientific evidence and belief. Commonly-held beliefs about matters that are the subject of scientific research are often contradicted by the research evidence, but such contradictory beliefs can persist over long periods, even being promoted by governments and other influential organizations.
The subject of the article, by US science writer Gary Taubes, is the relationship between exercise and weight loss. The commonly held belief is that regular exercise reduces body fat, but the scientific evidence shows very clearly that exercise is not directly related to body fat.
Instead, exercise increases hunger, and the way people eat in response to hunger determines whether they increase or decrease the amount of stored fat in their bodies. People who eat a lot of easily digested carbohydrates like sugars tend to store more fat than people who don’t.
To understand how this happens, including the role of insulin and lipoprotein lipase in the biochemistry of fat storage, you’ll have to read the article:
More interesting to me is Taubes’ analysis of the relationship between belief and science, and the kinds of influence that are at work.
The reason that the faulty belief in exercise is so commonly held turns out to be primarily the influence of one man, Jean Mayer, a Frenchman who made his name in America. He believed that hunger is directly related to blood glucose levels, despite research evidence to the contrary, so he ignored the well-known relationship between exercise and hunger:
It helped that Mayer promoted his pro-exercise message with a fervor akin to a moral crusade. In 1966, Mayer was the primary author of a U.S. Public Health Service report advocating increased physical activity along with diet as the best way to lose weight. In 1969, Mayer chaired Richard Nixon’s White House Conference on Food, Nutrition, and Health… In 1972, Mayer began writing a syndicated newspaper column on nutrition…
Taubes blames science journalism and the influence of public bodies for contributing to the distortion of the truth:
As for the authorities themselves, the primary factor fueling their belief in the weight-maintaining benefits of exercise was their natural reluctance to acknowledge otherwise… Clinicians, researchers, exercise physiologists, even personal trainers at the local gym took to thinking and talking about hunger as though it were a phenomenon exclusive to the brain, a question of willpower (whatever that is), not the natural consequence of a body trying to replenish itself with energy.
In an earlier article, Taubes examined the effects of fat in the diet. Again, the establishment view is not supported by the scientific evidence. In this case the science is far from clear cut, but again belief systems outweigh the research, leading to official advice to the public that is scientifically baseless:
In the face of this uncertainty, skeptics and apostates have come along repeatedly, only to see their work almost religiously ignored as the mainstream medical community sought consensus on the evils of dietary fat. For 20 years, for instance, the Harvard School of Public Health has run the Nurses’ Health Study and its two sequelae — the Health Professionals Follow-Up Study and the Nurses’ Health Study II — accumulating over a decade of data on the diet and health of almost 300,000 Americans. The results suggest that total fat consumed has no relation to heart disease risk…yet not one government agency has changed its primary guidelines to fit these particular data.
The relationship between fat consumption and obesity is distorted by belief systems in a similar way:
The hypothesis that low-fat diets are the requisite route to weight loss has taken a similar downward path… “This is held almost to be a religious truth,” says Harvard’s [Professor] Willett. Considerable data, however, now suggest otherwise. The results of well-controlled clinical trials are consistent: People on low-fat diets initially lose a couple of kilograms, as they would on any diet, and then the weight tends to return. After 1 to 2 years, little has been achieved.
(Walter Willett is a Professor of Medicine and chairs Harvard University’s Department of Nutrition.)
If you are interested in the complicated historical and other details, including how low-fat diets can cause weight gain, you can read the full article (originally published in Science) here:
What does any of this have to do with psychotherapy? It’s that psychotherapy in the UK, like dietary advice, has become the business of government agencies and other influential organizations. These bodies appear to recognize scientific research as the basis for the advice they hand out, but behind that appearance there are belief systems that persist in the face of conflicting scientific evidence.
The result is that widely publicized claims about mental health by public bodies are no more likely to be trustworthy than widely publicized claims about diet. In both fields, science, pseudo-science and beliefs intermingle in a complex way to produce the ‘official line’.
The official line on psychotherapy is that CBT is optimally effective for the commonest mental illnesses, and that this claim is ‘evidence based’. But if you look at the scientific evidence, it’s a mess. There’s no meaningful definition of CBT, and very very little hard evidence being produced by the researchers.
This will all come crashing down. It might take a long time for new belief systems to permeate the establishment, but eventually they will. And they will be ‘evidence based’ too, or have some similar supporting buzzword.
Sadly, dumbed-down official beliefs that are not actually true cause people harm. People who are mentally ill could very often have effective treatment. How to do it is widely known in certain circles, but not widely believed in establishment circles. Instead, the establishment view is that anything labelled with the magic letters C B T is ‘evidence based’ and therefore must be good, even if in reality it’s a fat lot of use.
- Professor David Colquhoun of University College London, whose website, DC’s Improbable Science, alerted me recently to Gary Taubes’ work. See: The Diet Delusion
- Oxfordshire nutrition specialist and writer Barry Groves, who republishes the second of Taubes’ articles I mention on his Second Opinions website.