Current practice guidelines for management of overweight and obesity recommend a program of diet, exercise, and behavior therapy for all persons with a body mass index (calculated as kg/m(2)) of at least 30 (and those with body mass index > or =25 plus two weight-related comorbidities). In this tripartite treatment--often referred to as lifestyle modification--behavior therapy provides a structure that facilitates meeting goals for energy intake and expenditure. Although standard behavior therapy reliably induces mean weight losses of approximately 10% of initial weight, these reductions are difficult to maintain. Some authors argue that a shift in focus from behavior change to cognitive change will improve long-term results of lifestyle modification programs. This review describes, in detail, the standard behavioral treatment of obesity and compares it with an alternative treatment model that is based in a cognitive conceptualization of weight control. A review of the literature suggests that the differences between standard behavior therapy and cognitive-behavioral therapy of obesity lie more in their underlying theories than in their implementation. Empirical comparisons of the long-term effects of these approaches are needed.