In 2006, I fractured my right hip and left ankle and spent four months off my feet, using crutches to get around only when I had to. I’d just run a marathon and thought for sure the abrupt drop in exercise would result in instant weight gain. But a funny thing happened; I lost about 10 pounds—and without ever feeling hungry.
Within a month of resuming running, the weight had piled back on.
There are numerous physiological reasons why I lost weight once I stopped exercising, and some of them are explained in a recent New York magazine article (“The Scientist and the Stairmaster,” Sept. 24, 2007) that questions the role exercise plays in many weight maintenance and weight loss programs. As author Gary Taubes puts it: “The one thing that might be said about exercise with certainty is that it tends to make us hungry. Maybe not immediately, but eventually. Burn more calories and the odds are very good that we’ll consume more as well.”
Sure, if you reduce the calories you take in and increase those you expend, you will lose weight, at least initially. But the article explains that our bodies will attempt to do an end-run around that initiative and override willpower through the hormonal regulation of fat cells. As Taubes explains:
Ultimately, the relationship between physical activity and fatness comes down to the question of cause and effect. Is Lance Armstrong excessively lean because he burns off a few thousand calories a day cycling, or is he driven to expend that energy because his body is constitutionally set against storing calories as fat? If his fat tissue is resistant to accumulating calories, his body has little choice but to burn them as quickly as possible: what Rony and his contemporaries called the “activity impulse” physiological drive, not a conscious one. His body is telling him to get on his bike and ride, not his mind. Those of us who run to fat would have the opposite problem. Our fat tissue wants to store calories, leaving our muscles with a relative dearth of energy to burn. Itís not willpower we lack, but fuel.
Taubes also contends those who do lose weight after adopting a strenuous exercise regime probably also made a concerted effort to eliminate the kinds of foods that stimulate insulin production. “Rare is the person who decides the time has come to lose weight and doesn’t also decide perhaps it’s time to eat fewer sweets, drink less beer, switch to diet soda, and maybe curtail the kind of carb-rich snacks—the potato chips and the candy bars—that might be singularly responsible for driving up their insulin and so their fat,” he wrote.
So if you find you’re gaining, or at least no longer losing, weight while upping your mileage, it may be what you’re consuming after a workout or later in the day or week.