By Dr Ananya Mandal, MD
Gastric bypass surgery is one of the weight loss procedures available to patients who are dangerously overweight. The procedure is only carried out in people who have an excessive amount of body fat despite trying to lose weight using other methods such as dieting, exercise and medication.
These individuals are offered surgical intervention to reduce their risk of death and the complications associated with morbid obesity. Bariatric surgery is the term used to refer to gastric bypass and other forms of weight loss surgery such as gastric banding. These bariatric procedures help reduce people’s food intake and weight.
What happens in gastric bypass surgery?
In a typical gastric bypass operation, a small pouch in the top part of the stomach is created. This pouch is then connected to a segment of the small intestine, meaning the rest of the stomach and bowel is bypassed. Because the pouch is small, the stomach size is effectively reduced, leading to a decrease in its functional volume and therefore the amount of food that can be ingested at any one time.
The surgery can reduce the size of the stomach by as much as 90% or more. The patient then requires less food to feel full as well as absorbing less calories from any food they do eat. Furthermore, the pouch is created in an area where the stomach tissue is least likely to stretch and accommodate increasing amounts of food. This means that the size of the pouch remains more or less constant in the long term.
Benefits of gastric bypass operation
Typically, dramatic weight loss is achieved after a gastric bypass. This reduces the risk of obesity-associated diseases. The risk of death due to obesity is also reduced after a gastric bypass operation, by nearly 40%.
On the other hand, the gastric bypass surgery itself is associated with a higher risk of complication and death than other forms of weight loss surgery.
Reviewed by Sally Robertson, BSc
Last Updated: Oct 8, 2014