Two thought-provoking pieces in The New York Times challenge our assumptions about dealing with obesity.

The first, a May 2 article by Gina Kolata, describes the experiences six years later of the contestants in season 8 of NBC’s reality show “The Biggest Loser.” It’s not good news. All but one of the 14 contestants studied have gained weight since the contest ended, and four are now heavier than they were before the contest started. The explanation is a discouraging one for all dieters. The contestants went to extreme lengths to loose weight over the course of the show—hours of exercise and tight controls on food intake. We’d expect those extraordinary efforts to be unsustainable, but we’d also expect them to be unnecessary. The habits and discipline picked up in losing the weight should be enough to sustain the new lower weight, right? Wrong. The contestants’ bodies responded with extreme measures to return to their former weights. Even six years later, the contestants’ metabolisms consume significantly fewer calories than they did before the weight loss—400 to 800 fewer calories per day. They also have significantly lower levels of leptin, a hormone that suppresses hunger. So in order to maintain weight, these people need to cut food intake significantly while dealing with intensified food cravings. Clearly the mathematical approach to weight loss—fewer calories in, more calories out—doesn’t tell the whole story of human physiology.

In a May 8 opinion piece, Sandra Aamodt, a neuroscientist, puts that study in context. She explains that all diets put dieters at risk of long-term weight gain. Diets change metabolic rates and hormone levels, but the act of dieting also increases stress and requires tuning out the body’s signals of when it is hungry and when it is full. Periods of successful dieting are often followed by binges of over-eating. Long-term studies, she reports, indicate that people who diet actually gain more weight than people who don’t. Further, Aamodt challenges the assumption that weight loss is important to long-term health: “. . . Our culture’s view of obesity as uniquely deadly is mistaken. Low fitness, smoking, high blood pressure, low income and loneliness are all better predictors of early death than obesity. Exercise is especially important: Data from a 2009 study (British Journal of Sports Medicine 2009; 43: 1-2) showed that low fitness is responsible for 16 percent to 17 percent of deaths in the United States, while obesity accounts for only 2 percent to 3 percent, once fitness is factored out. . . . This suggests that overweight people should focus more on exercising than on calorie restriction.”

Aamodt advocates a combination of mindful eating and regular exercise as a path to better health.

The research should certainly push us to rethink our approaches to obesity, dieting, and exercise, whether we our goal is to improve our personal health, the health of employees in our organizations, or the health of our communities.

I’m going for a walk!