Gastric Bypass Surgery is a proven form of weight loss. Patients can expect to lose 75-80% of their excess body weight in the first two years following surgery. It is a more extensive surgical procedure than the gastric band and sleeve gastrectomyand is non-reversible.

Gastric bypass operations are a surgically proven form of weight loss when combined with a supervised diet, physical activity and behaviour modification programme. They are generally recommended for patients with higher BMI i.e. a Body Mass Index of 40 or over.

There are several varieties of gastric bypass, but all involve the creation of a small stomach pouch to restrict food intake and reduce the absorption of calories and nutrients from food which causes effective weight loss results.

The considerable health benefits of a gastric bypass include:


There are 2 main types of Gastric Bypass procedure, both of which essentially reduce the size of the stomach pouch so that less food is absorbed.


1. Roux-en-Y Gastric Bypass (RGB)

With this procedure a small stomach pouch is created by stapling part of the stomach together or vertical banding. This limits how much food you can eat. Then, a Y-shaped section of the small intestine is attached to the pouch to allow food to bypass the duodenum as well as the first portion of the jejunum. This is demonstrated below:


We have listed here some of the more commonly asked questions from our patients about the Gastric Bypass procedure.

Q: How Do I Know If I’m Suitable For Gastric Bypass Surgery?

Usually patients most suitable to have a gastric bypass are those with a BMI in the range of 40 to 60+. However surgery is dependent upon a bariatric surgeon’s opinion. All of our weight-loss surgery patients have an in depth consultation to discuss the most relevant procedure for them,prior to surgery.

Q: How Long Does Gastric-Bypass Surgery Take?

This depends on the patient, the surgeon and whether it is being done as an open or closed (keyhole) procedure. Open gastric bypass operations usually take 90-120 minutes, but laparoscopic bypasses may take up to twice as long to perform.

Q: How Long Will I Be In Hospital?

For open operations, most patients are discharged on the third or fourth post-operative day. Patients who have the laparoscopic procedure can go home on the second or third post-operative day.

Q: What Are The Benefits Of Gastric Bypass Surgery?

For the seriously obese, the benefits of the gastric bypass procedure very much outweigh the risks. In general: 75% of patients are expected to lose 75 to 80% of their excess body weight, most of which is lost in the first two years following surgery. Major improvements in risk factors for heart disease and cancer. Around 70-80% of patients with hypertension will be off medication and cholesterol levels will fall. Most type II diabetics will be cured. There will be major improvements in a whole range of weight-associated conditions. These could include sleep apnoea, asthma, joint pain, arthritis, reflux, fatigue, shortness of breath. Patients report less depression, improved self-esteem and confidence along with an overall increased sense of well-being.

Q: What Are The Risks Of Gastric Bypass Surgery?

As with any surgery, there are operative and long-term complications and risks associated with gastric bypass, including: Bleeding (haemorrhage). Complications due to anaesthesia and medications. Infections. Pulmonary emboli (blood clots on the lung). Deep vein thrombosis. Dehiscence (wound breakdown). Leaks from staple line. Injury to the spleen. Marginal ulcers. However, in experienced hands the risks of the procedure nowadays are very small. Most published reports show that the overall mortality rate for gastric bypass surgery is less than 1%. It’s also important to note that not only does bypass result in reduced absorption of calories, it may also reduce absorption of important vitamins and minerals such as iron, vitamin B-12 and calcium. Deficiencies in these nutrients can lead to many problems. Iron deficiency causes anaemia and weakness and deficiencies in calcium can cause osteoporosis. Lack of daily B-12 can lead to neurological problems. This is why patients undergoing gastric bypass are recommended to take a daily vitamin and mineral supplement. “Dumping syndrome,” in which the consumption of sugar causes abdominal cramping and diarrhoea, can also occur. Some people will also regain some weight in subsequent years.


Whether you have a gastric band, bypass, sleeve or balloon, your weight loss procedure is only the start of your journey. All these procedures are tremendous tools for weight loss and you can lose dramatic amounts of body weight, but it’s not entirely effortless. You DO have to work with it and you DO need aftercare following obesity surgery.

Gastric Bypass Aftercare