The Gastric Bypass, or stomach bypass, is considered by obesity experts to be the gold standard of modern bariatric surgery, and the benchmark for other bariatric procedures.

How it’s done

There are two main steps in Roux en Y Gastric Bypass surgery. First, we cut a small pouch from the top of the stomach, from which the rest of the stomach is separated (figure 1). This greatly reduces the size of the stomach, causing the patient to feel full early during a meal. Second, we connect this pouch to the small intestine (jejunum), bypassing the main stomach and much of the intestine (figure 2). This allows fewer calories to be absorbed from food by the intestinal lining (figures 3 and 4)


Figure 1

Figure 2

Figure 3

Figure 4


The gastric bypass procedure can be done either by open surgery, with an incision in the upper abdomen, or by laparoscopic (keyhole) surgery. The latter involves a small video camera and tiny instruments inserted into small holes in the abdomen: it results in less pain, fewer scars and most often a faster recovery.


Hospital time varies from three days after laparoscopic surgery to four days after open surgery. The patient will feel discomfort for several days after the operation, and will be unable to digest solid foods as the body adjusts to the surgery. In order to prevent blood clots, it is essential that the patient wears anti-thrombotic stockings and takes injections of light molecular heparins (blood thinner) for ten days after the operation.

Dietary requirements

After surgery, the patient will be able to consume only small quantities of food; some patients will experience further restrictions on specific food-types. A dietician will be available to offer personalised advice.

Results and success-rates

The Roux en Y Gastric Bypass method is unique in that it diminishes both the intake of food and the absorption of energy from that food. This malabsorption, however, is considerably less severe than the results of specific malabsorptive procedures, such as biliopancreatic diversion, and it does not cause diarrhoea, bad odours or serious deficiencies in vitamins or other minerals.

Most patients can achieve a 60-90 percent loss of their excess body weight, and maintain long-term weight loss with great success. Even more important is the improvement of general health: serious disorders such as diabetes, high blood-pressure and cholesterol levels, degenerative arthritis and sleep apnoea may improve or even vanish after surgery.


There are risks associated with all bariatric surgeries; these include peritonitis—a leak from the stomach or lower intestine into the abdominal cavity -and internal bleeding, which sometimes necessitates relaparoscopy. Infections and hernias are also possible, but much rarer.

After surgery there is the possibility of other symptoms, such as iron and vitamin B12 deficiencies, stomach ulcers and ‘dumping’. Dumping occurs when food moves too quickly through the stomach or small intestine, causing nausea, sweating and faintness. To avoid these symptoms, an appropriate low-calorie diet is prescribed.