Obesity remains a leading public health problem because of its complications, prevalence, and resistance to change, despite record rates of dieting. Risk factors exist at both population and individual levels, thus obesity has diverse etiologies and consequences. Dieting is often grounded in the notion that the body can be molded at will and that the rewards justify the effort, creating a drive for unrealistic goals. This article argues for establishing a "reasonable weight," which may differ from health and aesthetic ideals. Intervention is less a matter of finding a "best" treatment but of finding the approach with "best fit" for the individual. Advances in treatment are most likely when research is driven by theory on the etiology of weight gain, the relapse process, and methods for permanent behavior change. This article integrates information on etiology, social beliefs about body weight, theory, and treatment into a comprehensive and compassionate model for intervention.