Obesity may be linked to additional chronic health conditions, or comorbidities, including type 2 diabetes, high blood pressure, high cholesterol levels, depression, cancer, and sleep apnea.

When people with obesity want to lose weight but haven’t been able to lose weight or keep it off through conventional methods like diet, exercise, or medication, bariatric surgeries may help treat obesity and potential comorbidities.

Bariatric procedures are a set of weight loss surgeries that can help some people lose weight by changing the anatomy of the digestive system.

Duodenal switch surgery — also known as biliopancreatic diversion with duodenal switch (BPD/DS) — is a bariatric procedure sometimes recommended for people with “extreme” obesity, or those with a body mass index (BMI) greater than 50.

Although it’s less common than other weight loss surgeries, BPD/DS has been gaining popularity in the United States.

Research suggests that, compared with other bariatric surgeries, this procedure may allow people to lose more weight, better maintain weight loss, and experience greater improvement in obesity-related complications.

Still, it comes with more postoperative risks than other weight loss procedures.

This article examines BPD/DS, including its potential benefits and downsides.

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BPD/DS is a two-step procedure — the first step involves the stomach, and the second involves the small intestine, or duodenum:

  • First step (gastric sleeve): This step involves a gastric sleeve surgery, one of the most common bariatric surgeries in the United States, in which a part of the stomach is removed, leaving the stomach the size of a banana.
  • Second step (duodenal switch): This step requires cutting the duodenum — the first part of the small intestine — and connecting it to the last 250 centimeters of the small intestine, bypassing roughly two-thirds of the small intestine.

Reducing the size of the stomach limits the amount of food you can consume, making you feel full sooner. Reducing the size of the small intestine limits the number of calories and nutrients your body can absorb from food.

Therefore, this surgery is associated with greater weight loss than other bariatric procedures.

Despite the surgery’s potential for success, not everyone qualifies for it.

The eligibility criteria for BPD/DS include:

  • BMI greater than 50
  • difficulty losing weight or maintaining weight loss via nonsurgical weight loss strategies
  • mental health clearance that screens for psychological disorders, such as depression, anxiety, and eating disorders
  • no medical contraindications to surgery, such as pregnancy, substance misuse, or other health risks

The preoperative evaluation also includes a nutritional assessment to guide patients through the postsurgery dietary changes they’ll need to follow for greater surgery success.

A surgeon may encourage a low carbohydrate diet to reduce the size of the liver before surgery and reduce the chance of postoperative complications.

Learn more about who is eligible for weight loss surgery.


Studies suggest that people at higher body weights are disproportionately likely to experience disordered eating and eating disorder symptoms. A significant number of people who explore and undergo bariatric surgery have eating disorders.

If you are preoccupied with food or your weight, feel guilt surrounding your food choices, or routinely engage in restrictive diets, consider reaching out for support. These behaviors may indicate a disordered relationship with food or an eating disorder.

Disordered eating and eating disorders can affect anyone, regardless of gender identity, race, age, body size, socioeconomic status, or other identities.

They can be caused by any combination of biological, social, cultural, and environmental factors — not just by exposure to diet culture.

Feel empowered to talk with a qualified healthcare professional, such as a registered dietitian, if you’re struggling.

You can also chat, call, or text anonymously with trained volunteers at the National Eating Disorders Association helpline for free or explore the organization’s free and low cost resources.

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While it potentially offers greater weight loss results than other bariatric procedures, this surgery also comes with greater risks, which can be divided into early and late complications.

Early complications: Anastomotic leaks, hemorrhage, blood clots

Common early complications, which are similar to those of other bariatric surgeries, include:

  • Anastomotic leaks:Anastomosis” is the medical term used to describe the reconnection of two ends of a passage — in this case, the duodenum and the last part of the small intestine. Anastomotic leaks occur when the connection doesn’t hold and intestinal contents leak. Symptoms include fever, infections, and tachycardia (fast heart rate).
  • Hemorrhage: “Hemorrhage” is another term for internal bleeding. Depending on the site of the bleeding, a person may require an additional operation or a blood transfusion to repair the tissue or prevent blood loss.
  • Deep venous thrombosis (DVT): DVT occurs when a blood clot forms in the deep veins of your legs, arms, or brain. This increases the risk of stroke.

Both anastomotic leaks and hemorrhages can be severe complications that require re-operation, leading to longer hospitalizations, reduced quality of life, and higher medical expenses.

Late complications: Potential for malnutrition and nutrient deficiencies

As for common late complications, the main concern is nutrient deficiency. In fact, BPD/DS is associated with more postsurgery malnutrition and metabolic-related complications than other types of bariatric surgery.

Nutrients typically get digested and absorbed in different parts of the digestive tract. However, after the procedure, food doesn’t pass through most of the small intestine. Therefore, there’s a marked reduction in the absorption of certain nutrients.

Common nutritional deficiencies include protein malnutrition and deficiencies in vitamins and minerals, including iron; calcium; B vitamins such as B1, B12, and folate; and fat-soluble vitamins such as vitamins A, D, E, and K.

Nutritional deficiencies can negatively affect reproductive function, metabolic health and weight management, blood pressure regulation, blood sugar regulation, vision, thinking ability and memory, and more.

Thus, BPD/DS requires lifelong micronutrient supplementation.

Pros of duodenal switch surgery

  • It’s the most effective bariatric surgery for weight loss and long-term comorbidity improvement.
  • The procedure comes with a low rate of revision surgery needed to maintain weight loss.
  • It offers a higher type 2 diabetes remission rate than other bariatric procedures.
  • Animal studies show a better gut microbiota composition after surgery, which is linked to improved metabolic health.
  • It may provide long-term cost savings as a result of comorbidity reductions, as well as a drop in prescription drug purchases, medical visits, and hospitalization costs.

Cons of duodenal switch surgery

  • It’s the most complex bariatric procedure, requiring longer surgical times.
  • Compared with other bariatric procedures, it’s associated with the highest rates of postoperative complications and mortality.
  • The procedure presents an increased risk of nutritional deficiencies compared with other weight loss surgeries.
  • It’s linked to higher rates of digestive side effects such as bloating, gas, and increased bowel movements.
  • It may come with unexpected expenses for regular follow-up visits and supplements.
  • Some people may experience worsened mental health after bariatric surgery.
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BPD/DS is the most effective weight loss surgery for people with a BMI greater than 50. People tend to lose more weight and maintain more weight loss in the long term after this surgery than they do after other procedures.

However, like any other bariatric surgery, BPD/DS does not cure obesity. Also, while it promotes weight loss, that isn’t always guaranteed. (Remember, a number of factors influence weight, including genetics and hormones.)

Therefore, the procedure’s long-term weight loss success depends largely on adherence to postoperative lifestyle changes — such as diet and exercise — as these may help prevent you from regaining the lost weight.

According to the International Federation for the Surgery of Obesity and Metabolic Disorders, the typical or expected weight loss for BPD/DS is around 40% of initial weight, and there is a relatively low risk of weight regain.

Still, the results can vary from one person to another.

For instance, one 10-year study in 224 people who underwent BPD/DS determined that by years 2, 5, and 10 after surgery, the excess weight loss percentage was 81%, 69%, and 67%, respectively.

However, as mentioned before, the amount of weight you lose may depend on how strictly you follow certain weight maintenance strategies after surgery.

Aside from potentially reducing your weight, BPD/DS may increase your chances of improving health conditions such as high blood pressure, high blood cholesterol levels, fatty liver disease, sleep apnea, and diabetes.

In one study, 35 people showed complete type 2 diabetes remission by year 2, and 27 people by year 5.

Duodenal switch surgery, or biliopancreatic diversion with duodenal switch (BPD/DS), is the least common bariatric surgery.

It’s reserved for people with a BMI greater than 50 who have had difficulty losing weight or maintaining weight loss via nonsurgical weight loss strategies.

It’s a two-step procedure, consisting of a gastric sleeve surgery followed by a shortening of the small intestine. Thus, it limits your food intake and the number of calories and nutrients your body can absorb.

Despite being less common than other weight loss procedures, it can potentially provide the most weight loss, best weight maintenance, and highest rates of improvement of obesity-related complications.

However, it also comes with the greatest risks, including long-term nutritional deficiencies that may require lifelong supplementation.

Still, as with most other bariatric surgeries, its long-term effectiveness may depend partially on how closely you adhere to recommended lifestyle habits after the surgery, such as following a prescribed diet and exercising regularly to prevent weight regain.

A note on weight discrimination

Although studies often suggest that obesity is a risk factor for certain health conditions, they rarely account for the role weight stigma and discrimination play in health. Discrimination is one of the social determinants of health — the conditions in daily life that affect our health — and it can and does contribute to health inequities.

Weight discrimination in healthcare can prevent people at high body weights from seeking medical care — and those who do may not receive accurate diagnoses or treatment, because doctors may attribute their health concerns solely to their weight.

As a result, any health condition a person may have may be more advanced by the time they receive a diagnosis.

Meanwhile, experiences of weight stigma in daily life, even outside of medical settings, are associated with negative mental and physical health outcomes.

Everyone deserves appropriate and compassionate medical care. If you’re interested in finding weight-inclusive healthcare professionals, you may want to follow the work of the Association for Size Diversity and Health, which is developing a directory that will launch in 2022.

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