Improved diet through reduced calorie intake, and in particular reduction of sugar and fat consumption, is an established approach to weight loss. In conjunction with increased exercise, significant levels of weight reduction can be achieved. However, the success rates for these approaches are low, and typically weight gain is observed after some initial weight loss due to poor compliance with these lifestyle interventions.

For the morbidly obese bariatric surgery, such as gastric bypass or banding, often leads to significant weight loss but is associated with surgical risk.

Drug therapy can lead to weight loss. The mechanisms of existing drug therapies fall into two categories – centrally-acting appetite suppression (sibutramine, rimonabant) and peripheral inhibition of digestion and absorption of dietary fat (orlistat). The level of weight loss observed with these therapies is modest and associated with certain side-effects that limit their use in clinical practice.