Exercise bulimia, the abuse of exercise to control body weight, is believed to afflict several million American women and a smaller number of men, few of whom are thought to seek professional help. Instead of purging by inducing vomiting or taking laxatives, exercise bulimics run themselves into the ground to expend the "excess" calories they consume. It would not be unusual for an exercise bulimic, for example, to take two hour-long exercise classes a day in addition to running for 40 minutes, swimming for half an hour and biking for an hour.

Less studied, but perhaps more common today, is a phenomenon that some therapists have dubbed "exercise bulimia." … Instead of vomiting or taking laxatives, however, some bulimics purge by burning off calories with huge amounts of exercise.