Gary Taubes penned a column in Nature last month arguing for a rigorous test of the energy balance hypothesis versus what he calls the hormonal hypothesis for the cause of obesity. Taubes writes
Before the Second World War, European investigators believed that obesity was a hormonal or regulatory disorder. Gustav von Bergmann, a German authority on internal medicine, proposed this hypothesis in the early 1900s.
The theory evaporated with the war. After the lingua franca of science switched from German to English, the German-language literature on obesity was rarely cited. (Imagine the world today if physicists had chosen to ignore the thinking that emerged from Germany and Austria before the war.)
Instead, physicians embraced the ideas of the University of Michigan physician Louis Newburgh, who argued that obese individuals had a “perverted appetite” that failed to match the calories that they consumed with their bodies’ metabolic needs. “All obese persons are alike in one fundamental respect,” Newburgh insisted, “they literally overeat.” This paradigm of energy balance/overeating/gluttony/sloth became the conventional, unquestioned explanation for why we get fat. It is, as Bernard would say, the fixed idea.
This history would be no more than an interesting footnote in obesity science if there were not compelling reason to believe that the overeating hypothesis has failed. In the United States, and elsewhere, obesity and diabetes rates have climbed to crisis levels in the time that Newburgh’s energy-balance idea has held sway, despite the ubiquity of the advice based on it: if we want to lose fat, we have to eat less and/or move more. Yet rather than blame the advice, we have taken to blaming individuals for not following it ‘properly’.
The alternative hypothesis — that obesity is a hormonal, regulatory defect — leads to a different prescription. In this paradigm, it is not excess calories that cause obesity, but the quantity and quality of carbohydrates consumed. The carbohydrate content of the diet must be rectified to restore health.
As I have argued before (see here and here), these two hypotheses are not conflicting. The question of whether or not carbs make you fat is not an either-or issue but a quantitative one. I also agree that we don’t yet know the answer and a definitive carefully controlled experiment is required. I call this the “Land Sub Experiment” because what we need to do is to completely sequester individuals from the outside world for up to a year or more so that we can precisely measure everything they eat and how much energy they expend. We can then compare a group that consumes mostly carbs to one that doesn’t. The NIH will actually be involved in the NuSi study that Taubes describes and Kevin Hall is directly involved in the planning. I anxiously await the outcome. On a side note, a recent meta-analysis (see here) reports that being overweight actually lowers your mortality rate.