What is Gastric Bypass Surgery?

Commonly, an operation called a Roux-en-Y gastric bypass is done. During the surgery, your stomach is divided into two, creating a small upper stomach pouch.

A part of your upper bowel (small intestine) is then connected to this stomach pouch. This means that when you eat, food bypasses the main part of your stomach and the upper part of your small intestine. In this upper part of your small intestine, your food would normally start to be digested and taken up (absorbed) by your body. So, with this part of your intestine being bypassed, fewer calories are taken up from the food that you eat. Also, because the new stomach pouch that is created is smaller than the size of your whole stomach, the amount of food that you are able to eat is reduced, thereby restricting calories that you take in.