Duodenal switch (BPD/DS) and SADI-S explained: how they work, who is usually considered, long-term randomized results vs gastric bypass, deficiency rates, vitamins and calcium, risks, cost and insurance.
Fact-checked against FDA labels and official sources; not yet reviewed by a licensed clinician. This page is education, not medical advice. Talk to your doctor before starting, stopping or changing any treatment.
Key facts
- Type
- Medical
- Approach
- Surgical
- Sedation
- General anesthesia
- Downtime
- 2+ weeks
- Permanence
- Permanent
- Performed by
- Bariatric surgery
Key takeaways
- The duodenal switch bypasses roughly 75% of the small intestine, the most of any approved procedure.[1]
- In a randomized trial, total weight loss 13 to 17 years after a duodenal switch was 37.5%, versus 22.8% after a bypass, with more adverse events.[8]
- Deficiencies are common after BPD/DS: copper up to 90%, zinc up to 70% and iron 8% to 50%.[10]
- The guideline lists higher routine calcium after a duodenal switch (1,800-2,400 mg/day) than after other operations.[10]
- Medicare covers BPD/DS nationally for people who meet its criteria.[14]
In short: The duodenal switch (biliopancreatic diversion with duodenal switch, BPD/DS) combines a gastric sleeve with a long intestinal bypass that skips roughly 75% of the small intestine. It produces the most weight loss and the strongest effect on type 2 diabetes of the standard operations, but it also has the highest risk of vitamin, mineral and protein shortages and more side effects. A newer, simpler version with a single intestinal connection is called SADI-S. Together they made up about 2% of U.S. weight-loss procedures in 2023, and they are usually considered for people with very high BMIs or as a second operation after a sleeve.
This page explains how the duodenal switch and SADI-S work, who is usually considered, what randomized trials found over 5 and 15 years, the nutritional risks in detail, life afterwards, cost and insurance, and questions to ask. It is education only; InstaTuck does not sell or arrange surgery. Talk with a licensed doctor, ideally a surgeon experienced in this operation, and get a full evaluation before deciding.
Duodenal switch at a glance
- About 75%of the small intestine is bypassed in BPD/DS, the most of any standard operationASMBS
- 6,162duodenal switch operations in the U.S. in 2023 (BPD/DS 3,775 + SADI 2,387)ASMBS estimates
- 37.5%total weight loss 13 to 17 years after BPD/DS vs 22.8% after bypass (randomized trial)Obesity Surgery 2023
- Up to 90%copper deficiency reported after BPD/DSASMBS 2016 nutrition guideline
Checked on October 6, 2026
What a duodenal switch is
The NIH describes the operation as two procedures in one. First, the surgeon makes a gastric sleeve, removing a large part of the stomach. Second, the small intestine is divided and rerouted so that food bypasses most of it and meets the digestive juices from the liver and pancreas only over a shorter stretch, so fewer calories, fat and nutrients are absorbed. ASMBS notes that roughly 75% of the small intestine is bypassed, the most of any approved procedure, and that the operation is complex with a longer operating time.
SADI-S (single anastomosis duodeno-ileal bypass with sleeve gastrectomy) is a simplified version. After the sleeve, the duodenum is connected to a loop of the lower small intestine with only one connection. ASMBS lists its advantages as effective long-term weight loss and type 2 diabetes remission, a simpler and faster operation than gastric bypass or BPD/DS, and a good option for revision after a sleeve; its disadvantages are poorer vitamin and mineral absorption than a sleeve or band, limited outcome data because it is newer, reflux risk and possibly loose, frequent bowel movements.
| Item | BPD-DS | SADI |
|---|---|---|
| 2020 | 3,555 | 488 |
| 2021 | 5,525 | 1,025 |
| 2022 | 6,096 | 1,567 |
| 2023 | 3,775 | 2,387 |
Best estimates. SADI was counted separately from 2020. BPD-DS was 1,422 in 2011.
Source: ASMBS, Estimate of Bariatric Surgery Numbers, 2011-2023, and 2025 fact sheet (checked on October 6, 2026)
How it works
The duodenal switch works in three ways at once. The sleeve limits how much fits in the stomach. The long bypass reduces how much fat and many nutrients are absorbed, because food and digestive juices mix over a shorter length of intestine. And, as with other metabolic operations, changes in gut hormones affect appetite and blood sugar. Compared with a gastric bypass, the absorption effect is much stronger, which explains both the larger weight loss and the higher nutritional risk.
Who is usually considered
The 2022 ASMBS and IFSO guidelines set the general thresholds for metabolic and bariatric surgery (recommended for a BMI over 35, considered from 30 with metabolic disease) and leave the choice of operation to the surgical team. In practice, the trials of the duodenal switch enrolled people with very high BMIs (50 to 60 in the Scandinavian trial), and the switch is often discussed as a second step after a sleeve. ASMBS describes it as the most effective option for type 2 diabetes, with slightly higher complication rates. Because of the lifelong nutritional demands, it is worth discussing honestly with your team whether you can take several supplements every day, attend regular blood tests and follow-up, and eat enough protein. Medicare covers open and laparoscopic BPD/DS nationally for people with a BMI of 35 or more, an obesity-related condition and previous unsuccessful medical treatment.
What the studies show
Two randomized trials compared the duodenal switch with gastric bypass in people with super obesity. In a trial at Oslo University Hospital and Sahlgrenska University Hospital (60 patients, BMI 50 to 60), BMI fell by an average of 22.1 points five years after a duodenal switch versus 13.6 after a bypass, with greater improvements in LDL cholesterol, triglycerides and blood sugar but more surgical, nutritional and digestive side effects. In a Swedish single-center trial of 47 patients with a BMI over 48, followed for 13 to 17 years, total weight loss was 37.5% after a duodenal switch and 22.8% after a bypass, HbA1c and LDL were lower, but hemoglobin was also lower and adverse events were about three times as frequent (2.7 versus 0.9 per patient).
| Item | Duodenal switch | Gastric bypass |
|---|---|---|
| BMI points lost at 5 years (Oslo and Gothenburg) | 22.1 | 13.6 |
| Total weight loss % at 13-17 years (Sweden) | 37.5 | 22.8 |
| Adverse events per patient at 13-17 years | 2.7 | 0.9 |
Small trials (60 and 47 patients). 5-year data: https://doi.org/10.1001/jamasurg.2014.3579. Mixed units: read each row on its own.
Source: Risstad H et al., JAMA Surgery 2015; long-term follow-up, Obesity Surgery 2023 (checked on October 6, 2026)
Larger U.S. registry data show the switch is also more demanding in the short term. In an analysis of 3,378 people with a BMI over 50 who had a first BPD/DS in the MBSAQIP registry (2015 to 2018), 30-day readmission or emergency visits were 12.9%, reoperation or reintervention 5.7%, major morbidity 3.4% and mortality 0.4%; for a BPD/DS done as a revision (487 people), major morbidity was higher at 5.3%. For comparison, ASMBS puts the overall risk of death across bariatric surgery at about 0.1%.
Nutrition: the biggest trade-off
The NIH says the duodenal switch is the operation most likely to cause shortages of vitamins, minerals and protein. The 2016 ASMBS nutrition guideline reports very high rates of deficiency after BPD/DS: copper up to 90%, zinc up to 70%, vitamin A up to 70% within four years (bypass and BPD/DS together), and iron 8% to 50%. Because fat is poorly absorbed, the fat-soluble vitamins A, D, E and K need special attention, and the guideline lists higher routine calcium (1,800 to 2,400 mg a day from all sources, versus 1,200 to 1,500 mg after other operations) and higher vitamin A and K amounts after a duodenal switch. These are the guideline’s general figures; your team sets your own plan from blood tests.
| Item | Low | High |
|---|---|---|
| Band, sleeve or bypass | 1,200 mg | 1,500 mg |
| Duodenal switch | 1,800 mg | 2,400 mg |
General guideline ranges, not a personal dose: your team adjusts supplements to your blood tests.
Source: Parrott J et al., ASMBS Integrated Health Nutritional Guidelines 2016 Update: Micronutrients (checked on October 6, 2026)
Protein matters too. The NIH lists protein shortage among the risks of this operation, and the 2019 AACE, TOS and ASMBS guideline describes a long-term diet after BPD/DS of small, nutrient-dense meals high in protein, with fruits, vegetables, whole grains and omega-3 fats, and no concentrated sweets. The guideline’s checklist calls for follow-up visits at about 1 month, then every 3 months until stable and every 6 months after that, with blood tests for iron, folate, vitamin D, parathyroid hormone, vitamin A, and copper, zinc and selenium when symptoms suggest a problem, plus a bone density scan at about two years. Our life after bariatric surgery guide explains the tests and diet stages.
Other risks and side effects
ASMBS lists slightly higher complication rates than other operations, reflux risk (from the sleeve part) and looser, more frequent bowel movements as disadvantages. Early surgical risks are the same as for other operations: bleeding, infection, leaks, blood clots and, rarely, death. Over time, the 2019 guideline notes a higher risk of gallstones during rapid weight loss after a sleeve, bypass or duodenal switch, the NIH lists bone loss (osteoporosis) and anemia among nutritional complications, and the long-term trial found lower hemoglobin after a duodenal switch than after a bypass. Changes in alcohol absorption and the advice to avoid pregnancy for 12 to 18 months apply here as after other operations, and the 2019 guideline advises discussing non-oral contraception after malabsorptive procedures.
Duodenal switch, bypass and sleeve compared
| Duodenal switch (BPD/DS) | Gastric bypass | Gastric sleeve | |
|---|---|---|---|
| Stomach | Sleeve | Egg-sized pouch | Sleeve (about 80% removed) |
| Intestine bypassed | Roughly 75% of the small intestine | Reconnected about 3 to 4 feet downstream | None |
| Weight loss | The most of the standard operations | More than sleeve on average | Less than bypass on average |
| Routine calcium in the ASMBS guideline | 1,800 to 2,400 mg a day | 1,200 to 1,500 mg a day | 1,200 to 1,500 mg a day |
| Zinc deficiency reported | Up to 70% | 40% | 19% |
| U.S. procedures in 2023 | 3,775 (plus 2,387 SADI) | 63,132 | 157,254 |
Day to day, life after a switch is built around protein and supplements: the 2019 guideline’s long-term advice is small, nutrient-dense meals high in protein, with fruits, vegetables, whole grains and omega-3 fats and no concentrated sweets, and its checklist lists at least two multivitamin-with-mineral tablets a day plus calcium, vitamin D and other nutrients by blood test. Our nutrition, high-protein eating and protein calculator pages help with planning.
Cost and insurance
ASMBS gives an average cost range for bariatric surgery overall of $17,000 to $26,000 (checked on October 6, 2026); it does not give a separate figure for the duodenal switch, which is a longer operation, and lifelong supplements and lab tests add ongoing costs. Medicare covers open and laparoscopic BPD/DS nationally for people who meet its criteria. We did not find a Medicare statement specifically on SADI-S; ask your plan how it classifies it. See our insurance hub and costs hub.
Alternatives and comparisons
The gastric bypass gives less weight loss with fewer nutritional problems; the gastric sleeve is simpler still and can be converted to a duodenal switch later if needed, as a revision. Medicines such as Zepbound and Wegovy are an option before or after surgery; see GLP-1 vs bariatric surgery. The bariatric surgery guide compares every operation, and our bariatric surgeons guide explains how to find an accredited center; for a duodenal switch, ask specifically how many the surgeon has performed.
Who explores it
General thresholds from the 2022 ASMBS/IFSO guidelines (BMI over 35, or 30 to 34.9 with metabolic disease); trials enrolled people with very high BMIs (50 to 60), and the operation is also used as a revision after a sleeve. Requires lifelong supplements and follow-up.
How it works
A gastric sleeve plus an intestinal bypass: the duodenum is connected to the last part of the small intestine so food and digestive juices mix over a short stretch, bypassing roughly 75% of the small intestine (ASMBS). SADI-S uses a single connection to a loop of lower intestine.
Typical results
BMI reduction of 22.1 points at 5 years vs 13.6 after bypass (randomized, BMI 50-60); total weight loss 37.5% at 13 to 17 years vs 22.8% after bypass (randomized, 47 patients).
Ranges from published studies; individual results vary.
Recovery
Hospital recovery and a staged diet as after other operations, followed by a long-term high-protein diet, several daily supplements and regular blood tests for life (2019 AACE/TOS/ASMBS guideline).
Risks
- Highest risk of vitamin, mineral and protein shortages (NIDDK): copper up to 90%, zinc up to 70%, vitamin A up to 70%, iron 8-50% (ASMBS 2016)
- More adverse events than bypass in long-term trials (2.7 vs 0.9 per patient)
- 30-day readmission or ED visit 12.9%, reoperation 5.7%, mortality 0.4% in people with BMI over 50 (MBSAQIP)
- Looser, more frequent bowel movements and reflux (ASMBS)
- Anemia, bone loss and gallstones
- Bleeding, infection, leaks, blood clots and, rarely, death
Cost and insurance
| Price | Amount | Basis | Checked on |
|---|---|---|---|
| Typical total (national data) | 17,000-26,000 USD | average cost range for bariatric surgery overall (ASMBS; not duodenal switch-specific) | October 6, 2026 |
Prices change often and depend on pharmacy, plan and location. Insurance can change what you pay. Every price shows the date we checked it.
Medicare covers open and laparoscopic BPD/DS nationally for people with a BMI of 35 or more, an obesity-related condition and previous unsuccessful medical treatment. No Medicare statement specific to SADI-S was found; ask your plan.
Insurance information checked on October 6, 2026.
Advantages and limitations
Advantages
- The most weight loss of the standard operations (ASMBS, NIDDK)
- Most effective for type 2 diabetes according to ASMBS
- Can be done as a second step after a sleeve
Limitations
- Highest risk of vitamin, mineral and protein deficiencies; demanding lifelong supplements
- More complications and side effects than bypass in long-term trials
- Looser, frequent bowel movements
- Complex surgery done at fewer centers; SADI-S has limited long-term data
Choosing a provider
Check board certification, where the procedure is done (accredited facility), how many of these procedures the provider performs, and what follow-up care is included. Find a Bariatric Surgeon: credentials, accredited centers and what to ask
Alternatives
FDA approved for weight managementPrescriptionInjectionZepbound (tirzepatide): uses, side effects, cost and FDA statusTirzepatide: how the dual GIP/GLP-1 drug works (Zepbound, Mounjaro) · Injection · Weekly
SurgicalGastric Bypass: how it works, results and long-term careSurgical · 2+ weeks
SurgicalGastric Sleeve Surgery: eligibility, results, risks and costSurgical · 2+ weeks
SurgicalRevision Bariatric Surgery: why, options, results and risksSurgicalRelated procedures
Research mentioning it
Related guides
Bariatric Surgery: types, eligibility and life afterBariatric surgery explained: sleeve, bypass, duodenal switch and band compared, the 2022 eligibility guidelines, results, risks,…
Life After Bariatric Surgery: diet stages, vitamins, follow-up and the long termLife after bariatric surgery: guideline diet stages, protein, vitamins and minerals for life, follow-up visits and…
Find a Bariatric Surgeon: credentials, accredited centers and what to askHow to find a qualified bariatric surgeon: board certification, MBSAQIP accredited centers, the evaluation steps, risks,…Tools for this topic
Questions to ask a professional
- Why a duodenal switch or SADI-S for me rather than a bypass?
- How many of these operations have you performed, and what are your complication rates?
- Which supplements will I need every day, and how often will my blood be tested?
- What should I expect about bowel movements, protein intake and bone health?
- If I already have a sleeve, what are the risks of converting it?
Frequently asked questions
What is a duodenal switch?
An operation that combines a gastric sleeve with a long intestinal bypass, so food and digestive juices mix only near the end of the small intestine. ASMBS says roughly 75% of the small intestine is bypassed.
How much weight do you lose with a duodenal switch?
More than with other standard operations. In a randomized trial of people with very high BMIs, total weight loss 13 to 17 years later was 37.5% after a duodenal switch versus 22.8% after a bypass.
What is SADI-S?
Single anastomosis duodeno-ileal bypass with sleeve gastrectomy: a simplified duodenal switch with one intestinal connection. ASMBS notes it is simpler and faster but newer, with limited outcome data.
Why is the duodenal switch done less often?
It is a complex, longer operation with the highest risk of vitamin, mineral and protein shortages and more side effects, so it is usually reserved for selected people, such as those with very high BMIs or as a revision.
What vitamins do you need after a duodenal switch?
Several, for life: guidelines list a multivitamin with minerals, higher calcium than after other operations, vitamin D, and higher vitamin A and K, with blood tests for iron, zinc, copper and fat-soluble vitamins. Your team sets your plan.
Does a duodenal switch cause diarrhea?
ASMBS lists looser, more frequent bowel movements as a disadvantage, because less fat is absorbed.
Is a duodenal switch covered by insurance?
Medicare covers BPD/DS nationally for people who meet its criteria. Private plans vary; ask how they classify SADI-S.
Can a sleeve be converted to a duodenal switch?
Yes, the switch and SADI-S can be done as a second step after a sleeve; ASMBS lists SADI-S as a good option for revision after a sleeve.
References
- Bariatric Surgery Procedures. American Society for Metabolic and Bariatric Surgery. (accessed October 6, 2026) Society statement
- Estimate of Bariatric Surgery Numbers, 2011-2023. American Society for Metabolic and Bariatric Surgery. (accessed October 7, 2026) Society statement
- 2025 Fact Sheet: Metabolic and Bariatric Surgery (incl. SADI and OAGB counts). American Society for Metabolic and Bariatric Surgery, 2025. (accessed October 7, 2026) Society statement
- Types of Weight-loss Surgery. National Institute of Diabetes and Digestive and Kidney Diseases (NIH). (accessed October 6, 2026) Government page
- Side Effects of Weight-loss Surgery. National Institute of Diabetes and Digestive and Kidney Diseases (NIH). (accessed October 6, 2026) Government page
- Eisenberg D, Shikora SA, Aarts E, et al.. 2022 ASMBS and IFSO: Indications for Metabolic and Bariatric Surgery. Surgery for Obesity and Related Diseases, 2022. doi:10.1016/j.soard.2022.08.013 · PMID 36280539 (accessed October 6, 2026) Guideline
- Risstad H, et al.. Five-year outcomes after laparoscopic gastric bypass and laparoscopic duodenal switch in patients with body mass index of 50 to 60: a randomized clinical trial. JAMA Surgery, 2015. doi:10.1001/jamasurg.2014.3579 · PMID 25650964 (accessed October 6, 2026) Randomized trial
- Long-term Follow-up 15 Years After Duodenal Switch or Gastric Bypass for Super Obesity: a Randomized Controlled Trial. Obesity Surgery, 2023. doi:10.1007/s11695-023-06767-0 · PMID 37584851 (accessed October 6, 2026) Randomized trial
- Safety of Primary Versus Revisional Biliopancreatic Diversion with Duodenal Switch in Patients with Super Obesity Using the MBSAQIP database. Obesity Surgery, 2022. doi:10.1007/s11695-022-05953-w · PMID 35137289 (accessed October 6, 2026) Other
- Parrott J, Frank L, Rabena R, et al.. ASMBS Integrated Health Nutritional Guidelines for the Surgical Weight Loss Patient 2016 Update: Micronutrients. Surgery for Obesity and Related Diseases; American Society for Metabolic and Bariatric Surgery, 2017. PMID 28392254 (accessed October 6, 2026) Guideline
- Mechanick JI, Apovian C, Brethauer S, et al.. Clinical Practice Guidelines for the Perioperative Nutrition, Metabolic, and Nonsurgical Support of Patients Undergoing Bariatric Procedures: 2019 Update (AACE/TOS/ASMBS/OMA/ASA). Endocrine Practice, 2019. doi:10.4158/GL-2019-0406 · PMID 31682518 (accessed October 6, 2026) Guideline
- American Society for Metabolic and Bariatric Surgery updated statement on single-anastomosis duodenal switch. Surgery for Obesity and Related Diseases, 2020. doi:10.1016/j.soard.2020.03.020 · PMID 32371036 (accessed October 6, 2026) Society statement
- Metabolic and Bariatric Surgery (fact page, incl. average cost). American Society for Metabolic and Bariatric Surgery. (accessed October 6, 2026) Society statement
- National Coverage Determination 100.1: Bariatric Surgery. Centers for Medicare and Medicaid Services. (accessed October 7, 2026) Government page
Facts checked on October 6, 2026
Educational information, not medical advice. Talk with a qualified healthcare professional about your own situation. In an emergency call 911.