Are you sitting down? Are you ready to believe that everything you know is wrong? Because in the new issue of New York magazine, Gary Taubes writes that exercise does not make us thinner. The article is extremely long, but luckily, in the Wall Street Journal today, Bob Cwiklik breaks it down. Taubes admits that working out is great for your health, but, "the one thing that might be said about exercise with certainty is that it tends to makes us hungry." He suggests that what really determines how fat or lean a person is has more to do with the body's own internal programming. Taubes also questions the idea that exercise makes us feel better about ourselves, writing, "This may be purely a cultural phenomenon. It's hard to imagine that the French, for instance, would improve their self-esteem by spending more time at the gym."

Back in 1977, the National Institute of Health hosted its second conference on obesity and weight control. "The importance of exercise in weight control is less than might be believed," the assembled experts concluded. And still, the workout culture of the 80s exploded, aerobics, Jazzercise and all.

But, Taubes argues, it's not exercising that affects your weight. It's the way your body is wired.

The key is that among the many things regulated in this homeostatic system—along with blood pressure and blood sugar, body temperature, respiration, etc.—is the amount of fat we carry. From this biological or homeostatic perspective, lean people are not those who have the willpower to exercise more and eat less. They are people whose bodies are programmed to send the calories they consume to the muscles to be burned rather than to the fat tissue to be stored—the Lance Armstrongs of the world. The rest of us tend to go the other way, shunting off calories to fat tissue, where they accumulate to excess. This shunting of calories toward fat cells to be stored or toward the muscles to be burned is a phenomenon known as fuel partitioning.

The real news here is that, like the South Beach or Atkins diets purport, carbs seem to be the problem. "If we eat fewer carbohydrates—in particular the easily digestible simple carbohydrates and sugars — we might lose considerable fat or at least not gain any more, whether we exercise or not." We're off to buy some beef jerky.


The Scientist and the Stairmaster [New York]
Exercise Will Make You Healthy, But Probably Not Thinner [WSJ]