Obesity is a major health problem in America. Weight loss is associated with improvements in obesity-related health complications, but patients and practitioners are frequently disappointed by the long-term results of weight control efforts. Recent research has yielded new findings concerning the causes of obesity, as well as new goals for obesity treatment. Traditionally, the goal of therapy has been reduction to ideal weight. Several scientific bodies, however, now recommend a more modest 5% to 15% reduction in initial weight. Current options for weight loss include behavioral or pharmacological management provided during primary care visits, self-help and commercial programs, hospital-based interventions, and bariatric surgery. Regardless of the approach selected, long-term care usually is required to facilitate the maintenance of weight loss.