We know how hard it is to lose weight and keep it off, and yet we do it to be healthier. But do you have to lose weight to be healthy? Not necessarily. One important reason that obesity is unhealthy is the decreased likelihood of being physically and aerobically fit. If you could change that underlying loss of physical fitness, then you could become healthier without losing weight. Of course, physical fitness requires effort to maintain, just as weight loss does. However, body mechanisms often undermine weight loss efforts and bring your weight back, so that the struggle to maintain weight loss is often harder than the weight loss itself. Not so with physical fitness. The more fit you are, the easier it is to exercise. And the benefits of exercise are greater than the benefits of weight loss at virtually any weight.
Lisa Sanders, M.D., is an assistant professor at the Yale School of Medicine and author of the Diagnosis column for the New York Times Magazine.