Gastric Bypass Surgery

This page will provide you with information about gastric bypass surgery. For further details, please speak to your consultant.

What is gastric bypass surgery?

This form of weight-loss surgery – also known as a Roux-en-Y gastric bypass procedure – works by reducing the amount of calories absorbed by the body after eating. It does this by:

1) Reducing the size of the stomach

2) Bypassing part of the intestinal tract

Gastric bypass surgery is very popular amongst those suffering with obesity and looking to lose weight. It can help them to shift a significant amount of weight if traditional methods such as diet and exercise have failed to produce results. As obesity can be linked to a number of serious health problems, gastric bypass surgery can help to minimise the risk of these as well.

If you are:

  • Morbidly obese (have a BMI measure 40 or above)
  • Found to have a high BMI (35 or over) but also suffer from diabetes, heart disease or high blood pressure
  • Fit to be put under anaesthetic and undergo surgery
  • Unable to shift a significant amount of weight from diet or exercise

Then gastric bypass surgery may be the right choice for you.

What will happen during the operation?

A surgeon will use staples to create a small compartment at the top of the stomach; a piece of intestine will then be moved and attached to this compartment. This will create a system that bypasses the rest of the stomach and the upper part of the intestine – where the majority of calories are absorbed.

The small, upper compartment created with the staples fills up easily, meaning the patient is able to eat less. Fewer calories are also absorbed due to the new system bypassing the section of the small intestine where most calorie absorption occurs. The food then travels through the rest of the digestive system.

Risks and complications

Any risks or complications will be discussed in advance of your treatment with your expert consultant.


Most patients stay in hospital for around 3 days after their surgery. During this time hospital staff will ensure the patient is fit and healthy and ready to return home.



EIDO Healthcare Limited – The operation and treatment information on this website is produced using information from EIDO Healthcare Ltd and is licensed by Aspen Healthcare.

The information should not replace advice that your relevant health professional would give you.

Gastric Bypass Surgery Consultants