Weight-loss surgery (aka bariatric surgery) consists of a group of surgical operations designed to achieve both meaningful and sustainable weight loss. These procedures involve surgically manipulating the stomach (and sometimes the small intestines) to reduce food intake, and, in some cases, to reduce the absorption of calories into the body. The procedures include:

• Adjustable gastric banding: This common surgery achieves weight loss solely by restricting how much food one can eat.
  
  
• Gastric bypass: This common surgery achieves weight loss not only by restricting how much food one can eat, but also through hormonal changes, appetite reduction, food intolerances and mild malabsorption, in which the body absorbs fewer calories and nutrients.
  
  
• Biliopancreatic diversion: A less commonly performed operation, in which the intestines are bypassed, this achieves weight loss predominantly by limiting the absorption of calories consumed.
  
  
• Vertical sleeve gastrectomy: Also less common, this procedure involves removing part of the stomach. It is a new procedure and the exact mechanism of action has not yet been determined.
  

Currently, all of these procedures can be and are performed laparoscopically, meaning that surgeons operate through several small incisions with the aid of a video camera rather than through a long incision. This means less risk of complications, quicker healing, and less scarring.