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Types of weight loss surgery

Operations and procedures to help reduce a person's weight may be an option if other measures, such as diet and medication haven’t worked.

The NHS only considers funding this type of surgery for people with potentially life-threatening obesity, when other measures have not been effective.

Procedures are also available privately.

Like any operation, weight loss surgery carries risks.

How weight loss surgery works

Weight loss surgery works in two ways: by restriction and malabsorption.

  • Restriction: This kind of weight loss surgery works by preventing the stomach from stretching to full size. Normally, the stomach can hold 1.5 litres of food. After weight loss surgery, the stomach can hold only around a quarter of a litre. This results in feeling full faster, eating less, and losing weight.
  • Malabsorption: Some weight loss operations also divert food around a section of intestine. By skipping an area of intestine fewer calories are absorbed. Lower calorie absorption leads to weight loss.

Most weight loss surgery today is laparoscopic. In laparoscopic surgery, four to six small incisions are made in the abdominal wall. The surgeon inserts tools and a camera through these holes and then operates while watching a video screen.

In open surgery (laparotomy), the surgeon makes a large incision along the middle of the abdomen. This is sometimes necessary, when the surgery cannot be done laparoscopically.

Types of weight loss surgery

Gastric bypass surgery

There are two parts to a gastric bypass:

  • The surgeon divides the stomach into a large portion and a much smaller portion. The small stomach portion is then stapled into a small pouch.
  • The small stomach pouch is disconnected from the first part of the small intestine (the duodenum). The surgeon reconnects the small stomach pouch to the second part of the small intestine (the jejunum).

After gastric bypass, a smaller amount of food makes a person feel full. He or she eats less and loses weight. Appetite is also reduced. Food also bypasses some of the stomach and a small part of the intestine. This reduces absorption of vitamins and minerals, but doctors now think that there is probably not a significant reduction in calorie or protein absorption.

Laparoscopic adjustable gastric banding

The gastric banding procedure involves the following:

  • Using laparoscopic tools, the surgeon places an inflatable silicone band around the upper stomach.
  • The band is tightened so the stomach becomes a small pouch with a narrow outlet.
  • Afterwards, the patient feels full faster, eats less, and loses weight.
  • The band can be tightened or loosened, to minimise side effects and improve weight loss.

Gastric banding is considered a less invasive weight loss operation and the procedure can be reversed if necessary.

Bilio-pancreatic diversion

  • Like a gastric bypass, the surgeon divides the stomach and creates a small pouch, but the remainder of the stomach is removed.
  • The surgeon then connects the small stomach pouch to an even further-down section of intestine, compared with gastric bypass.
  • After bilio-pancreatic diversion, the stomach is small, and food bypasses a large amount of intestine. The person both eats less and absorbs fewer calories, causing weight loss.

Bilio-pancreatic diversion is less widely carried out than either gastric banding or gastric bypass. It is highly effective, but is difficult to perform. Also, bilio-pancreatic diversion frequently leads to nutritional deficiencies.

Sleeve gastrectomy

This type of operation is for people with a BMI of 60 or greater and for whom gastric banding or gastric bypass would not be safe.

It involves removing a section of the stomach therefore reducing the size of the stomach by around 75%. Following weight reduction it should then be possible to safely perform gastric banding or bypass.

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