An impassioned debate over the virtues and dangers of dieting is polarizing the field and diverts attention from key issues. Dieting clearly has costs and, for some, has the potential for benefit. The primary challenges are (a) to identify individuals who will be helped or harmed by dieting, (b) to reduce the frequency and severity of dieting in those for whom the costs exceed the benefits, (c) to better understand the physiological and psychological reasons why some people can lose and others cannot, and (d) to develop safe and effective means for weight loss and its maintenance and to target these methods to individuals who stand to benefit.