Dietary treatments of obesity.

Dietary treatment of obesity is based on one or another of two premises: that the obese eat too much or that they eat the wrong things. The first is a tautology lacking explanatory power. The second is a meaningful and promising hypothesis but has yet to be effectively applied. At present, virtually all outpatient treatments of obesity, including behavior modification, are based on the first premise and consist of strategies for reducing the subject's caloric intake. Most such interventions produce short-term weight loss. Regain after the end of treatment remains the usual outcome. A survey of studies published in the period 1977-1986 and reporting on dietary or behavioral treatment of obesity reveals that the maximum percentage of body weight lost is, on average, 8.5 percent--no different from the value, 8.9%, in similar studies from 1966-1976, as reviewed by Wing and Jeffery. The principal determinant of success in such programs appears to be the intake weight of the subjects: the higher the intake weight, the more successful the intervention will appear to be. The goals and research methods of studies on dietary treatments for obesity are overdue for ethical as well as scientific reevaluation. The same may be said for the numerous programs providing such treatment outside the context of research.