1. Gastric bypass, in which the esophagus is essentially connected directly to the small intestine. This reduces caloric intake at the expense of considerable potential adverse effects.
2.Gastric banding, also referrred to as bariatric surgery, compresses the stomach by means of an external mechanical device. Appetite and capacity are reduced resulting in gradual weight loss.
3.Above-knee amputation produces weight reduction in a biphasic pattern. The immediate post-operative drop is supplemented by a long-term increase in caloric expenditure derived from hopping.