A gastric bypass is an operation performed on obese people to greatly decrease the size of the stomach, resulting in less food being consumed and fewer calories absorbed. Gastric bypass surgery is a last resort option after diets, exercise, and other therapies have failed, and is a fairly drastic procedure. However, it can result in extremely successful and sustained weight loss.

This article on gastric bypass surgery is written by Jackie Griffiths, a freelance journalist who writes health, medical, biological, and pharmaceutical articles for national and international journals, newsletters and web sites.

One person in a hundred will die from obesity surgery so it is not something to go into lightly; on the other hand, if these individuals stayed obese they are at greater risk from dying from obesity-related conditions such as heart disease, diabetes, and cancer. A recent study showed that obese people who have obesity surgery are 40% less likely to die over the next seven to ten years than those who do not have the surgery.

However you do it, it’s vital to get your weight down as soon as possible if you are obese.

What is it?

Sometimes known as ‘stomach stapling,’ the gastric bypass operation is recommended to be undertaken for medical reasons rather than cosmetic. During the procedure, a small pouch is created at the top of your stomach by sealing off the rest, leaving only a small portion of the stomach open and able to receive food. This is then attached to the small intestine, bypassing the rest of the stomach and a part of your bowel, meaning that not only do you eat much smaller portions and feel full sooner, but you absorb few calories from the food you do eat. On average, people tend to lose 60-70% of their excess weight within two years.

What happens during the operation?

There are two ways to conduct the gastric bypass operation: using keyhole surgery or the open surgery technique. Depending on which method your surgeon uses, you will either stay in hospital for about three days or a week.

A small pouch at the top part of your stomach will be created using staples to close off the main part of your stomach. A small section of your intestine is then removed and reattached to the bottom of the pouch. If you’re having keyhole surgery, openings are made in your abdomen and chest and the surgeon uses a telescopic camera to see inside. After the operation, you will have a few stitches to close each cut. If you decide to go for open surgery, a single opening is made in your abdomen and there is no need for a camera. The cut is closed using stitches and staples.

There are many bacteria present in your bowel so you will be given antibiotics during the operation, and afterwards, to prevent infection.

Who can have it?

If you’re over the age of 12 and have a BMI of over 40 (or over 35 if you also suffer from one of the serious illnesses caused by obesity, such as diabetes or heart-disease) you are eligible to have a gastric bypass on the NHS. However, there are very long waiting lists and it might be quicker to opt for private treatment. A private gastric bypass operation can cost between £10,000 - £12,000.


After gastric bypass surgery, you lose large amounts of weight, fast, without the need for exercise or diets. Having said that, it is strongly advised to add exercise to your lifestyle in order to help keep the weight off.

  • Feeling full sooner, and for longer
  • Double action weight loss – restricting food intake and reducing calorie absorption
  • Peace of mind knowing it’s a permanent solution providing life-long change


  • DVT in the veins in the leg
  • Accidental damage to other organs
  • Infection
  • Leaking (in the intestine join)
  • Gallstones (if weight loss is too rapid)
  • Death

Life after the operation

  • You will still be able to get pregnant
  • You do not have to be 'super' obese to qualify for a gastric bypass
  • You will still be able to enjoy eating out
  • You can still consume alcohol
  • After you have fully recovered and adjusted your eating habits you’ll still be able to enjoy a normal diet (only in greatly reduced portions)

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