A product of affluence and changing life-styles, obesity has become one of our most prevalent and serious nutritional problems. It is estimated that there are more than 10 million adolescents and young adults in the United States who are obese; most will remain so in spite of periodic attempts at weight control. Most physicians have little objection to treating a bright, young, highly motivated middle-class adolescent girl who is only slightly overweight. It is the passive, physically inactive youngster with longstanding obesity who elicits a feeling of futility, hopelessness, and despair on the part of the physician. Our present therapeutic approaches to the obesity problem produce notoriously poor results. If one uses weight loss solely as the criterion of success, there is little evidence that treatment of juvenile obesity by most current methods (caloric restriction, exercise, and counseling) produces better long-term results than no therapy at all. Evaluation of measures