Anyone who has tried to lose weight and keep it off knows how difficult the task can be. It seems like it should be simple: Just exercise to burn more calories and reduce your calorie intake. But many studies have shown that this simple strategy doesn't work very well for the vast majority of people.
A dramatic example of the challenges of maintaining weight loss comes from a recent National Institutes of Health study. The researchers followed 14 contestants who had participated in the "World's Biggest Loser" reality show. During the 30 weeks of the show, the contestants lost an average of over 125 pounds per person. But in the six years after the show, all but one gained back most of their lost weight, despite continuing to diet and exercise.