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What Is Duodenal Switch Surgery?

Duodenal switch surgery generates weight loss by restricting the amount of food that can be eaten and by limiting the amount of food that is absorbed into the body. The stomach is restricted in size by dividing it vertically and removing more than 85%; this part of the surgery is not reversible. The stomach that remains is shaped like a thin banana and measures from 4 to 7 ounces. The nerves to the stomach and the outlet valve remain intact with the idea of preserving the functions of the stomach while reducing the volume. In addition, the intestines are divided and rearranged to separate food from the digestive juices, creating malabsorption. The food limb is attached to the duodenum and receives food from the stomach and is 150 cm long. The digestive juices are not separated from the food and travel over 500 cm in the bypassed small intestine. Both food and digestive juices mix together and travel for 100 cm in the common limb. As a result, food and digestive juices are separated for the most of the length of the intestines. This prevents patients who have had this surgery from absorbing all of the calories that are eaten.

Who is a good candidate for duodenal switch surgery?


If you have a body mass index (BMI) greater than 40, you may be a candidate for the procedure; others with lower BMIs, but with obesity-related illnesses such as diabetes may also be candidates. It may be effective for people with very high BMIs of greater than 55. 


What are the risks of duodenal switch surgery?

As with any surgery, complications may happen and may include:


  • Bleeding/Blood loss
  • Blood clots
  • Infection
  • Leakage which means a perforation of the stomach or a leak from anywhere in the bowel is stitched together has occurred
  • Difficulty consuming liquids immediately after surgery, due to swelling around the stomach and small bowel
  • Nutritional deficiencies

  • The brittle bone disease osteoporosis due to a malabsorption of calcium and vitamin D, which are needed to maintain bone strength
  • Night blindness due to malabsorption of Vitamin A
  • Malabsorption of protein, leading to malnutrition which may lead to a second operation
  • Carbs can be well absorbed resulting in inadequate weight loss
  • Chronic diarrhea. You may have multiple loose bowel movements in a day
  • Foul-smelling stools and gas

How should I prepare for the duodenal switch surgery?

Preparing for any weight loss surgery starts with making a lifelong commitment to the dietary and lifestyle changes necessary for success. Weight loss surgery is not a quick fix, and it is not a decision to enter into lightly. 

Once you and your physician have made a decision to have a duodenal switch surgery, the pre-operative evaluations can begin and may include:

  • Meeting with a registered dietician to discuss how your diet needs to change both before and after weight loss surgery.
  • A comprehensive evaluation by a mental health professional.
  • An upper endoscopy exam may be performed to make sure no polyps, tumors, ulcers or bacteria that cause ulcers are in the stomach prior to surgery.
  • Additional pre-operative evaluations may be necessary for the heart and lungs.
  • You’ll need to tell your physician any medications you are taking, including prescriptions and over-the-counter medicines, vitamins, herbs, and supplements.

Some of the lifestyle changes start before surgery and can include:

  • Quitting smoking for at least six to eight weeks before and after the surgery. Smoking can increase the risk of complications including potentially fatal blood clots. Smoking also increases the risk of pneumonia and other lung problems after surgery.
  • Not drinking alcohol for at least 48 hours before surgery.
  • Losing 5 to 10% of excess body weight; people who lose a moderate amount of weight before weight loss surgery can have a short hospital stay and more rapid postoperative weight loss.

What to expect after surgery

The duodenal switch procedure can often last three to four hours, and most patients require about three to four weeks of recovery. Part of the recovery process involves getting re-accustomed to eating solid foods. People who have the procedure can consume only fluids immediately following surgery. From there, they will progress to pureed foods and ultimately solids. Some patients can experience difficulty consuming liquids immediately after surgery because of swelling around the stomach and small bowel. In these cases, readmission to the hospital for a day or two may be necessary to rehydrate.

Pain may also occur following the surgery; your physician may prescribe painkillers to take after the surgery.

Most of the weight loss with the duodenal switch occurs during the first 12 to 18 months after surgery. Based on patient averages, you may lose about 70% of your current weight and about 35% of your BMI.

Compliance with nutrition guidelines is absolutely mandatory for duodenal switch patients because failure to comply can lead to malnutrition and significantly unpleasant bowel changes.