Here’s some quotes from an article on diet by Gary Taubes. I was struck by how similar the intransigence of the calories in/calories out crowd is to the same of the grammar teachers. (from http://www.bmj.com/content/346/bmj.f1050)
Medicine today is often taught untethered from its historyâ€”unlike physics, for instanceâ€”which explains why the provenance of the energy balance hypothesis is little known, even by those physicians and researchers who are its diehard proponents. Nor is it widely known that a competing hypothesis ever existed, and that this hypothesis may have done a better job of explaining the data and the observations. Knowing this history is crucial to understanding how we got into the current situation and, indeed, how we might solve it.
But this is not the case. One problem has been an almost ubiquitous misunderstanding of the alternative hypothesis and, indeed, of energy imbalance itself. The existence of an energy imbalance in people who are getting fatter is treated, as Newburgh did, as evidence that the energy balance hypothesis is correct. The same can be said for observations that obese people eat more than lean or are more sedentary, or even that per capita food availability has increased over the course of the obesity epidemic or that leisure time physical activity has decreased. All these observations, though, are consistent with both hypotheses.
Attempts to blame the obesity epidemics worldwide on increased availability of calories typically ignore the fact that these increases are largely carbohydrates and those carbohydrates are largely sugarsâ€”sucrose or high fructose corn syrup. And so these observations shed no light on whether it’s total calories to blame or the carbohydrate calories. Nor do they shed light on the more fundamental question of whether people or populations get fat because they’re eating more, or eat more because the macronutrient composition of their diets is promoting fat accumulationâ€”increased lipogenesis or decreased lipolysis, in effect, driving an increase in appetite.
Another problem endemic to obesity and nutrition research since the second world war has been the assumption that poorly controlled experiments and observational studies are sufficient basis on which to form beliefs and promulgate public health guidelines. This is rationalised by the fact that it’s exceedingly difficult (and inordinately expensive) to do better science when dealing with humans and long term chronic diseases. This may be true, but it doesn’t negate the fact the evidence generated from this research is inherently incapable of establishing reliable knowledge