12 Apr 2011 It’s not about the calories
The past few years have seen the launch of many admirable initiatives to solve the problem of childhood obesity in America, but I’d like to respectfully suggest that these programs are, quite simply, doomed to failure. This is not because the food industry will subvert their efforts. It’s not because the children and parents in this country lack the willpower to tackle this problem and certainly not because they lack the motivation. It’s because the advice these anti-obesity initiatives give isn’t going to help, and the science they’re based on is misguided, argues Gary Taubes (left), author of Why We Get Fat And What To Do About It, in this excellent article.
Take Michelle Obama’s Let’s Move! campaign, one of the most high-profile examples of this mistaken approach to the problem. The principles of Let’s Move! sound good. Who would be against getting kids to be more physically active and eat more fruits and vegetables? But anyone who thinks that will reverse the obesity epidemic is sorely mistaken.
Beneath all the program’s talk of making healthier food choices and increasing physical activity, its fundamental tenet is that we get fat because of the “overconsumption of calories.” This is how the White House’s Task Force on Childhood Obesity phrased the problem in its May 2010 report (PDF). And so the way to induce our children to lose weight is to get them to consume fewer calories, which they’ll do supposedly by eating less-energy-dense foods, and, of course, expending more energy through exercise—hence the name, “Let’s Move!”
This approach is certainly convenient. As Michelle Obama has said, it doesn’t require the “demonization of any industry.” All foods are OK in moderation, and the more our kids exercise, the more they can consume without getting fat. Follow this simple prescription and all will be well.
Except it won’t be. For the last 60 years, physicians and public-health authorities have been giving that exact same advice to obese people—children and adults—with little or no success. When researchers have tested diets that restrict how many calories are consumed—counseling their subjects to eat, say, 500 or 1,000 fewer calories a day than they normally would—the results have been depressingly predictable. The subjects experience modest weight loss (maybe nine or 10 pounds in the first six months), and then they gain the weight right back. Weight loss doesn’t last………..
The truth is, the conventional wisdom about why we get fat is simply wrong. It’s not about energy balance; it’s not about “overconsumption of calories” or “taking in more calories than we burn.” It’s about something else entirely: how the human body regulates fat metabolism and the accumulation of fat in our adipose tissue. This seems so obvious that it should go without saying—getting fat is a disorder of accumulating too much fat, so of course we should pay attention to how our bodies regulate fat accumulation —but this idea never managed to spread to the clinicians dealing with obesity, obsessed as they were with the notion that their patients were simply eating too much and exercising too little. (The 120-page Childhood Obesity Task Force report, tellingly, does not mention anything about how fat accumulation is regulated in the human body.) The real question to ask is why we accumulate fat—or more specifically, why our fat cells store more calories as fat than they release into the circulation to be burned for fuel.
So here is the answer: Fat accumulation in the human body is regulated fundamentally by the hormone insulin. If insulin levels increase, so does fat accumulation. If insulin levels decrease, fat is released from the fat cells and used for fuel. There’s nothing controversial about this fact. You can find it in most biochemistry and endocrinology textbooks, like this one that the Library of Medicine makes available online. It’s just considered irrelevant to the problem of obesity.