Biliopancreatic diversion

Surgery Overview

A biliopancreatic diversion changes the normal process of digestion by making the stomach smaller and allowing food to bypass part of the small intestine so that you absorb fewer calories.

You will feel full more quickly than when your stomach was its original size, which reduces the amount of food you eat and thus the calories consumed. Bypassing part of the intestine also means that you will absorb fewer calories. This leads to weight loss.

There are two biliopancreatic diversion surgeries: a biliopancreatic diversion and a biliopancreatic diversion with duodenal switch.

  • In a biliopancreatic diversion, a portion of the stomach is removed. The remaining portion of the stomach is connected to the lower portion of the small intestine. See a picture of a biliopancreatic diversion.
  • In a biliopancreatic diversion with duodenal switch, a smaller portion of the stomach is removed, but the remaining stomach remains attached to the duodenum (the upper part of the small intestine). The duodenum is connected to the lower part of the small intestine. See a picture of a biliopancreatic diversion with a duodenal switch.

These procedures can be done by making a large incision in the abdomen (an open procedure) or by making a small incision and using small instruments and a camera to guide the surgery (laparoscopic approach).

What To Expect After Surgery

Most people can return to their normal activities in 3 to 5 weeks. After biliopancreatic surgery, you generally see your surgeon 3 weeks after surgery and then every 3 months for 1 year. After 1 year, see your surgeon once a year.

A biliopancreatic diversion may cause dumping syndrome. This occurs when food moves too quickly through the stomach and intestines. It causes nausea, weakness, sweating, faintness, and possibly diarrhea soon after eating. These symptoms are made worse by eating highly refined, high-calorie foods (like sweets). Sometimes you may become so weak that you have to lie down until the symptoms pass. Dumping syndrome occurs less often in a biliopancreatic diversion with duodenal switch.

Why It Is Done

Many doctors will only consider this procedure for people who have not been able to lose weight with other treatments and who are at high risk for developing other health problems because of their weight.

Although guidelines vary, surgery is generally considered when your body mass index is 40 or higher or you have a life-threatening or disabling condition related to your weight.

The following conditions may also be required or are at least considered:

  • You have been obese for at least 5 years.
  • You do not have a history of alcohol abuse.
  • You do not have untreated depression or another major psychiatric disorder.
  • You are between 18 and 65 years of age.

All surgeries have risk. And it is important for you and your doctor to discuss your treatment options to decide what is best for you.

How Well It Works

Biliopancreatic diversion surgeries are effective. Most people lose 75% to 80% of their excess weight (the weight above what is considered healthy) and stay at their new weight.1


Risks common to all surgeries for weight loss include an infection in the incision, a leak from the stomach into the abdominal cavity or where the intestine is connected (resulting in an infection called peritonitis), and a blood clot in the lung (pulmonary embolism). About one-third of all people having surgery for obesity develop problems related to poor nutrition, such as anemia or osteoporosis.2, 3

Fewer than 10 out of 1000 people die after weight-loss surgery.4

Biliopancreatic diversion surgeries result in reduced absorption of protein, fat, calcium, iron, and vitamins B12, A, D, E, and K. You may have frequent, bad-smelling stools and a higher risk for developing osteoporosis.

Within 1 year of biliopancreatic diversion surgery:1

  • 30 out of 100 people develop anemia.
  • 30 to 50 people out of 100 develop a deficiency in vitamins A, D, E, K, and beta-carotene.
  • About 4 people out of 100 need hospitalization because of lack of protein. Protein deficiency is somewhat less of a risk in the biliopancreatic diversion with duodenal switch.

What To Think About

Biliopancreatic diversion surgeries are complex surgeries that should only be done by a very experienced surgeon.

Early studies of the laparoscopic approach to surgery for obesity suggest that it reduces recovery time and postsurgery complications.5 A laparoscopic approach for these surgeries has not been used long enough to draw significant conclusions.

In a biliopancreatic diversion, the part of the intestine where many minerals and vitamins are most easily absorbed is bypassed. Because of this, you may have a deficiency in iron, calcium, magnesium, or vitamins. To prevent vitamin and mineral deficiencies, you may need to work with a dietitian to plan meals. And you may need to take extra vitamin B12 as pills, shots, or nasal spray.

Complete the surgery information form (PDF)(What is a PDF document?) to help you prepare for this surgery.



  1. Brolin RE (2002). Bariatric surgery and long-term control of morbid obesity. JAMA, 288(22): 2793–2796.
  2. American Gastroenterological Association (2002). AGA technical review on obesity. Gastroenterology, 123(3): 882–932. [Erratum in Gastroenterology, 123(5): 1752.
  3. U.S. Department of Health and Human Services (2008). Bariatric Surgery for Severe Obesity (NIH Publication No. 04-4006). Available online:
  4. Maggard M, et al. (2005). Meta-analysis: Surgical treatment of obesity. Annals of Internal Medicine, 142: 547–559.
  5. Schauer PR, Ikramuddin S (2001). Laparoscopic surgery for morbid obesity. Surgical Clinics of North America, 81(5): 1145–1179.

Last Updated: April 16, 2009

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