Obesity is now recognized as a chronic disease. Its treatment implies a prolonged negative energy balance, by reducing caloric intake and/or increasing energy expenditure. In practice, three therapeutic approaches can be considered: 1) life-style modifications, combining well-balanced hypocaloric diet and regular physical exercise, the key-issue in obesity management; 2) in case of failure and as adjunct treatment, anti-obesity drugs, especially orlistat, an intestinal lipase inhibitor, and sibutramine, a central appetite regulator; and 3) in patients with extreme refractory obesity, surgical procedures consisting of gastric restriction (gastroplasty) or intestinal bypass. Anti-obesity treatments must be evaluated in the long run, in terms of efficacy/safety ratio, upon criteria of weight loss, reduction in associated risk factors, improvement of quality of life and, if possible, reduction of morbidity and mortality.