Gastric bypass surgery is when a significant part of the stomach is bypassed, so that the person requires less food to feel full, and therefore consumes fewer calories and loses weight.
It is one of the most common types of weight loss surgery, and usually allows for the quickest and most significant weight loss. However, it also has one of the highest risks of serious surgery complications, along with sleeve gastrectomy.
How does gastric bypass surgery work?
A surgeon will use surgical staples to create a small pouch at the top of the stomach, separating it from the lower part of the stomach. This is then connected to the small intestine, so food no longer passes through the lower part of the stomach or the first part of the bowel.
Because the rest of the stomach is now bypassed, the patient will be unable to consume as much food as they could before the surgery. This may help them lose up to 65 per cent of their excess weight within two years, and maintain the weight loss for 10 years.
The process is normally done using keyhole surgery, and generally takes one to three hours to complete. The patient will be instructed to follow a specific diet in the days and hours leading up to the operation.
Who can have a gastric bypass?
If someone has a BMI of 40 or more, or between 35 and 40 and has a condition which could be improved by losing weight (e.g. high blood pressure or type 2 diabetes), then they may be considered for a gastric bypass. People with a BMI of 50 or more may be offered gastric bypass surgery immediately.
Anyone who is considered for a gastric bypass will need to undergo several assessments to ensure the operation is suitable.
Ideally, weight loss will be achieved through a healthy diet and exercise, but not everyone succeeds through this method. If a person has unsuccessfully attempted to lose weight over a period of at least six months, their doctor may recommend them for weight loss surgery.