Some scientists have risked ridicule to tackle one of the best-attested facts of medical science: Almost all weight loss diets fail. Which prompts some questions about the unquestioned assumptions: If the Grand Idea is seldom or never demonstrated, maybe it’s a Grand Wrong Idea. As Mark Nugent explains in “Weighing the Evidence” (The American Conservative, September 1, 2011), some question the popular assertion that excess calories are simply stored as fat; therefore success means eating less and exercising more. It sounds so simple; why doesn’t it work?
Science journalist Gary Taube offers an alternative explanation,
Obesity is indeed associated with increased food intake and sedentary behavior, but conventional wisdom reverses cause and effect. If excess insulin triggers fat accumulation, the upshot is that an increased proportion of calories that would otherwise be available for the body to use as energy are diverted into fat storage. This translates into a higher caloric requirement that registers as hunger, overeating, and a sedentary lifestyle. Gluttony and sloth, Taubes argues, are the result, not the cause, of obesity.
In other words, you don’t feel like exercising because the calories that would have fuelled your energy are being whisked away, under the management of too much insulin, to build fat. He suggests lower carbohydrates, to slow the process.
So how did the current orthodoxy arise?
The proximate cause was simply scientific malpractice, as Taubes documented in his earlier book Good Calories, Bad Calories. In the 1960s and 1970s, scientists began to turn toward the idea that dietary fat and cholesterol cause heart disease. They improperly drew firm conclusions from epidemiological studies rather than from controlled, double-blind trials. They also tended to ignore studies whose conclusions disagreed with their already established beliefs. The public was harmed most of all by scientists’ good intentions: with the health of the nation at stake, many experts, feeling pressed to act quickly, believed they couldn’t wait for conclusive proof of their hypotheses before disseminating new dietary recommendations.
And, when it all didn’t work, they simply called for more of the same.
It’s a hard strategy to counter – in anything from obesity treatment to evolution theory – because the theorist’s failure to demonstrate the thesis is explained away as the hard, unbelieving hearts of the skeptics.
Many skeptics are simply people who can count, who realize that metabolisms are very complex, involving a number of inputs. Put another way: Yes, the Second Law of Thermodynamics is true – but so are a lot of other things that go into the final figure.
See also: Epigenetic signatures: Another blow to the “it’s in yer genes” industry