Gastric bypass surgery: the advantages, procedure and potential risks

Written by: Mr Sanjay Agrawal
Published: | Updated: 06/03/2020
Edited by: Top Doctors®

Gastric bypass surgery is a form of weight loss surgery that reduces your stomach by bypassing part of your digestive system. This restricts the appetite of the patient, allowing them to lose weight. The operation is done as a laparoscopic (keyhole) surgery procedure while the patient is under general anaesthetic. It usually takes between one and three hours. Patients tend to lose 60-70% of their excess body weight with a gastric bypass, more than with the gastric band or sleeve gastrectomy.


Gastric bypass surgery


Firstly, a small pouch is created at the top of your stomach using staples. A piece of your intestine is then joined to this gastric pouch. This bypasses the rest of your stomach and the upper part of the intestine, where most nutrients and calories are usually absorbed.

The new pouch at the top of the stomach fills up quickly with food, restricting the patient’s appetite. The food then travels straight to the middle part of your small intestine and through the rest of your digestive system. As the digestive system has effectively been made shorter, fewer calories are absorbed.

The bypass surgery can be performed as a standard open surgery, or as a laparoscopic surgery. The laparoscopic approach involves five or six very small incisions and has many advantages over open surgery, including quicker recovery, shorter hospital stays and a significantly reduced risk of infection.


What are the risks of gastric bypass surgery?


Gastric bypass surgery is generally safe, though, as with any operation, there are risks which patients should be aware of. These will differ from patient to patient but overall there is a 2-5% risk of adverse effects (many of which are those associated with any operation such as infection and risks associated with having a general anaesthetic) and a 0.5% risk of death. Typical side-effects are likely to include some bruising, pain and swelling.

In the long term, restricted diet may cause nutritional deficiency, vitamin and mineral supplements may need to be taken indefinitely.

By Mr Sanjay Agrawal

Mr Sanjay Agrawal is one of London's leading consultants in the specialty of bariatric, laparoscopic and upper GI Surgery and is certified as a 'Master Surgeon in Metabolic and Bariatric Surgery™ (MSMBS™)' by American Surgical Review Corporation. He is one of the country's prominent experts in obesity and weight loss surgery.

He also has a broad range of surgical expertise and performs surgery for gallstones and all kinds of hernias regularly. 

Mr Agrawal has undergone extensive training in the UK, Belgium, Japan and India and has undertaken more than 2,000 general surgical procedures so far. In addition, he has experience in over 1,250 laparoscopic bariatric procedures to date.

Mr Agrawal is Editor of the textbook titled "Obesity, Bariatric and Metabolic Surgery: A Practical Guide" which has achieved more than 190,000 individual chapter downloads worldwide so far. He is also Director of London International Bariatric Surgery Symposium (LIBSS).

Mr Agrawal is a well-respected and very active member of the medical community, dividing his time between consultation and surgery, teaching, committee membership, publishing books and articles and even finding time for television appearances as an expert in his field. 

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