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Biliopancreatic diversion with duodenal switch

Also sometimes called distal gastric bypass, this procedure is most commonly used for patients who have a Body Mass Index (BMI) of 50 or greater. (To determine your BMI, use our BMI Calculator.) It is always best to consult with your doctor to determine which procedure is right for you. Please visit the Contact Us page to learn how you can find a highly qualified, Center of Excellence surgeon in your area.

Description of the procedure

During the procedure, the surgeon first divides the stomach into two sections using staples. Unlike gastric bypass and vertical banded gastroplasty, which decrease stomach capacity to about 1 tablespoon, the “upper stomach” will hold about 6 ounces of food following the operation. One of the major differences between this procedure and the other options for weight loss surgery is that the remainder of the stomach is removed after the “upper stomach” has been created. However, to reduce the possibility of blockages, “dumping syndrome,” and other potential side effects, the pyloric valve, which allows food to pass from the stomach to the first part of the small intestine, remains intact.

Following the removal of the stomach, the surgeon connects the last section of the small intestine (also called the ileum) to the first part of the small intestine, or duodenum, which is normally attached to the stomach. The jejunum, or the middle part of the intestine, is bypassed. Because the intestine is shortened, there is less of an opportunity for the absorption of calories, which results in weight loss. However, there is also less of an opportunity for the body to absorb vitamins, minerals, and nutrients – which may result in malnutrition, anemia, or other deficiencies. Depending on the needs of the patient, the surgeon may adjust the amount of the small intestine that is left intact. A variation on this procedure, biliopancreatic diversion, reroutes the intestine in a different way. Your surgeon will be able to determine which procedure is best for you.


  • Biliopancreatic diversion often results in successful weight loss because fewer calories are absorbed. Many patients lose as much as 80% of excess weight (defined as weight above what is considered to be healthy) if they follow their doctor’s guidelines for behavioral changes, diet, and exercise following surgery.
  • Because the capacity of the stomach is greatly reduced, patients will not need to consume as much food (and, by extension, calories) to feel full.
  • Medical conditions related to obesity (such as hypertension and diabetes) will likely be improved or completely resolved as a result of the surgery. In the long term, you will decrease the chances of cardiovascular events and other weight-related complications compared to others in a similar situation who did not elect to have weight loss surgery.
  • As with any weight loss surgery, the loss of excess weight will enhance mobility and make it easier for you to participate in everyday activities.


  • As with any invasive, surgical procedure, bleeding, infection, and even death are risks.
  • Specific to most weight loss procedures is the risk of a leak into the abdominal cavity from the wall created by the staple line, which can cause peritonitis.
  • Blood clots may form (usually in the legs), and, if these move to the lungs, they can cause pulmonary embolism.
  • One of the most common side effects from this procedure is nutritional deficiencies that can cause or exacerbate osteoporosis or anemia in addition to other conditions.
  • In rare cases, patients will require hospitalization for protein deficiency.
  • To varying degrees, some patients may experience hair loss, which is commonly thought to be a result of insufficient protein and/or nutrient absorption.
  • Eating too much or too quickly may cause pain, nausea, vomiting, and/or severe discomfort.

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