FOR MANY PEOPLE in today's society, dieting has become not just a special way of eating but a way of life. Once practiced by relatively few Americans for specific medical conditions, dieting is now a common part of American culture. In fact, surveys indicate that at any one time, about 45 percent of women and 25 percent of men are dieting. In some cases, what starts as a healthy attempt at weight loss turns into an eating disorder.

The line between a normal concern about food and appearance and an abnormal obsession is not easily defined. At what point does a diet turn into an eating disorder? According to the authors of Surviving an Eating Disorder, "An eating disorder exists when one's attitude toward food and weight has gone awry—when one's feelings about work, school, relationships, day-to-day activities, and one's...