Gastric bypass surgery is a weight loss surgery by changing the way the stomach and small intestine handle the food. It makes the stomach smaller and reroutes the intestine. The stomach is divided into a small upper pouch and a much larger lower “remnant “pouch. This reduces the functional value of the stomach. The stomach fills soon and thus you eat less food. This results in altered physiological and physical response to food. A gastroenterologist performs the surgery. A general anesthesia is given before the surgery. First, the surgeon makes a small stomach pouch by stapling part of the stomach together or by vertical banding. This is also called laparoscopic band surgery. This is done to limit the quantity of food we eat. Next, the surgeon attaches a Y shaped section of the small intestine to the pouch. This creates a bypass for food and skips part of the digestive system .The result is fewer intakes of calories and nutrients. This method is known as Roux-en-Y. Another surgery is extensive gastric bypass, which is more complicated. The surgeon removes the lower part of the stomach. The remaining small part of the stomach is connected directly to the small intestine, completely bypassing the other two. It works as a weight loss, but is less recommended because of its complications. This is also referred to as gastric sleeve surgery. Most people adopting this surgery lose about ten to twenty pounds a month. Weight loss after surgery improves many medical conditions too.