Gastric Bypass Gastric Bypass is the most common gastric restrictive procedure.  Patients lose between 60% - 80% of excess weight over a period of 10 years.  It can be performed via laparoscopic surgery.  Gastric bypass surgery makes the stomach smaller by creating a small pouch at the top of the stomach using surgical staples or plastic band.  The smaller stomach is connected directly to the middle portion of the small intestine (jejunum), bypassing the rest of the stomach and the upper portion of the small intestine (duodenum). Weight loss is achieved via the following mechanisms:

1. Patient feels full more quickly than when stomach was its original size.
2. Patient feels full longer due to delay in emptying the intestine, the small diameter at the outlet and due to gastrojejunum anastomosis.
3. Patient experiences reduced appetite due to the reduction of ghrelin production hormone
4. A reduction of intestinal absorption by reducing the intestinal surface

Loss of excess weight at three years is approximately 65% and it effectively helps in reducing associated diseases such as:  diabetes mellitus by 80%, gastroesophageal reflux by 100%, hyperlipidemia by 90%, sleep apnea by 80% and arterial hypertension by 70%.  Thus, this is the reason it is called metabolic surgery.