Bariatric surgery explained: sleeve, bypass, duodenal switch and band compared, the 2022 eligibility guidelines, results, risks, insurance, surgery vs medication and choosing a surgeon.
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 takeaways
- The 2022 ASMBS/IFSO guidelines recommend metabolic and bariatric surgery for a BMI over 35 and say it should be considered from 30 with metabolic disease.[1]
- The sleeve made up 58.2% and gastric bypass 23.4% of about 270,000 U.S. bariatric procedures in 2023.[5]
- In the Swedish Obese Subjects study, gastric bypass patients kept off 25% of their weight at 10 years, and deaths were lower with surgery.[6]
- Follow-up procedures or hospital stays within 5 years affect about one in three people after weight-loss surgery, according to the NIH.[3]
- Lifelong vitamin and mineral supplements are essential after surgery to prevent deficiencies.[3]
In short: Bariatric (weight-loss) surgery changes the stomach, and sometimes the small intestine, to help people with obesity lose a large amount of weight and improve related conditions. The most common operations in the U.S. are the gastric sleeve and gastric bypass. The 2022 ASMBS and IFSO guidelines recommend surgery for people with a BMI over 35, and say it should be considered from a BMI of 30 for people with metabolic disease. Surgery brings lasting results for many people but also real risks and lifelong follow-up, including vitamins.
This guide covers the main types, who the guidelines say may be considered, what results and risks look like, cost and insurance, how surgery compares with medication, and how to choose a surgeon. It is general information; whether surgery is right for you is a decision for you and a qualified surgical team.
Types of bariatric surgery compared
According to ASMBS estimates, about 270,000 metabolic and bariatric procedures were done in the U.S. in 2023. The sleeve made up 58.2% of them and Roux-en-Y gastric bypass 23.4%; revisions of earlier operations were 11.9%, and duodenal switch, endoscopic sleeve gastroplasty, balloons and bands each made up 2% or less.
| Operation | What the surgeon does | What to know (NIH) |
|---|---|---|
| Gastric sleeve | Removes about 80% of the stomach, leaving a banana-shaped tube | More weight loss than a band; cannot be reversed; risk of vitamin and iron deficiency; reflux possible |
| Gastric bypass (Roux-en-Y) | Creates a small stomach pouch and connects it to a lower part of the small intestine | Greater weight loss on average than sleeve or band, but more complications after surgery; higher risk of vitamin and iron shortage; difficult to reverse |
| Duodenal switch (BPD-DS) | A sleeve plus rerouting of most of the small intestine | More weight loss than the other operations; most likely to cause vitamin, mineral and protein shortages; done rarely |
| Adjustable gastric band | Places an inflatable band around the top of the stomach | Least weight loss; needs adjustments; lowest vitamin risk; less common today because of complications and removals |
Revision surgery converts or repairs an earlier operation, for example when weight returns or reflux develops. Our gastric sleeve vs gastric bypass comparison goes deeper, and the medical procedures hub covers less invasive options such as the endoscopic sleeve gastroplasty and the gastric balloon.
Who may be considered: the 2022 guidelines
For three decades, eligibility followed a 1991 NIH consensus. In 2022, the American Society for Metabolic and Bariatric Surgery (ASMBS) and the International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO) updated it. Their statement says:
- surgery is recommended for people with a BMI over 35, whether or not they have weight-related conditions;
- surgery should be considered for people with metabolic disease and a BMI of 30 to 34.9;
- thresholds should be lower in Asian populations, where a BMI over 27.5 is the point at which surgery should be offered;
- appropriately selected children and adolescents should be considered.
Insurers often use their own, older criteria. Medicare, for example, covers bariatric surgery for people with a BMI of 35 or more, at least one obesity-related condition and previous unsuccessful medical treatment for obesity. A surgical team also looks at your overall health, your readiness for the lifelong changes and your support. Our BMI calculator gives a starting number; it is not an assessment for surgery.
Results: weight and health
The ASMBS and IFSO statement says long-term results of metabolic and bariatric surgery consistently show safety and efficacy. One of the longest studies is the Swedish Obese Subjects study, which followed 4,047 people for an average of 10.9 years. People who had gastric bypass had lost 32% of their weight after one to two years and kept off 25% at ten years; the older procedures in the study, banding and vertical-banded gastroplasty, led to smaller losses. Deaths were lower in the surgery group (adjusted hazard ratio 0.71). Surgery techniques have changed since that study began, and results differ from person to person.
The NIH notes that surgery can help people lose weight and improve many health problems related to obesity. Some weight regain over the years is common; it is a reason for follow-up, not a failure. Our keep it off hub covers maintenance after surgery.
Risks and side effects
The NIH lists short-term risks including bleeding, infection, leaks where the stomach or intestine is stapled or sewn, diarrhea, blood clots in the legs that can travel to the lungs or heart and, rarely, death. Longer-term risks include poor absorption of nutrients leading to anemia or bone loss, gallstones after fast weight loss, narrowing at the connections (strictures), hernias, band slipping or erosion, and changes in how the body handles alcohol, with a higher risk of alcohol problems. The NIH also reports that follow-up procedures, operations and hospital stays within five years are fairly common, affecting about one in three people, and more often after bypass than after a sleeve.
Preparing, recovery and life after
Ask your program what it requires before the operation, who you will see (for example a dietitian or a mental health professional), how eating is reintroduced afterwards and how long follow-up lasts. The NIH stresses that taking the prescribed vitamin and mineral supplements for life is essential to prevent deficiencies. Regular follow-up matters, and our guides to nutrition and strength training cover protein and muscle. Some people develop loose skin after large weight loss; see loose skin after weight loss.
Cost and insurance
Total cost depends on the operation, the hospital, the region and what the quote includes (surgeon, anesthesia, facility, follow-up). We publish prices only with a source and a date; see our costs hub. Medicare covers gastric bypass, duodenal switch and laparoscopic adjustable banding nationally for people who meet its criteria, and the laparoscopic sleeve at the discretion of local Medicare contractors; it does not cover gastric balloons. Private plans and Medicaid set their own criteria, so ask your plan for them in writing. Our insurance hub explains prior authorization and appeals.
Surgery or medication?
Newer medicines such as Wegovy and Zepbound have changed the conversation. They avoid an operation but are labeled for long-term use, and weight tends to come back after stopping; surgery is a one-time operation with lasting anatomical changes, surgical risks and lifelong supplements. The two can also be combined, for example medicine before or after surgery. We are not aware of a large trial comparing them directly in the general population with obesity, so cross-study comparisons have limits. Our GLP-1 vs bariatric surgery page lays out the trade-offs, and the medications hub lists the approved medicines.
Choosing a surgeon and a center
The Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP), run by the American College of Surgeons, accredits bariatric centers in the U.S. and Canada, and nearly 1,000 sites have been through its evaluation. Its website has a search for accredited centers. Ask the surgeon how many of your planned operation they perform, what their complication and readmission rates are, what the program includes before and after surgery, and how long follow-up lasts. Our bariatric surgeons guide explains how to check board certification.
Related guides
Tools for this topic
Latest research
A History of Bariatric Surgery: From 1954 to the SleeveA history of bariatric surgery from the original papers and FDA and Medicare records: the 1954…
Weight-Loss Devices FDA Has Authorized: Balloons, Capsules and MoreEvery weight-loss device the FDA has authorized, from the Lap-Band to swallowable balloons and gel capsules:…
Questions to Ask a Bariatric Surgeon (and How to Check Credentials)The questions to ask a bariatric surgeon and how to check credentials: American Board of Surgery…Questions to ask a professional
- Which operation would you recommend for me, and why that one?
- How many of these operations do you do each year, and what are your complication and readmission rates?
- Is your center accredited by MBSAQIP?
- What does the program include before and after surgery, and for how long?
- Which vitamins and lab checks will I need for life, and who will follow me?
Frequently asked questions
What BMI do you need for bariatric surgery?
The 2022 ASMBS/IFSO guidelines recommend surgery for a BMI over 35 and say it should be considered for a BMI of 30 to 34.9 with metabolic disease (lower thresholds in Asian populations). Insurers may use stricter criteria; Medicare uses a BMI of 35 or more with an obesity-related condition.
Which is better, the sleeve or the bypass?
Neither is best for everyone. The NIH notes bypass gives somewhat more weight loss on average but more complications and a higher risk of vitamin shortages; the sleeve cannot be reversed and can worsen reflux. A surgeon weighs these against your health.
How much weight do people lose after bariatric surgery?
It varies by operation and person. In the long-running Swedish Obese Subjects study, gastric bypass patients had lost 32% of their weight at one to two years and 25% at ten years.
Is bariatric surgery covered by insurance?
Often, with criteria. Medicare covers certain operations for people with a BMI of 35 or more, an obesity-related condition and prior unsuccessful medical treatment. Private plans and Medicaid vary; ask your plan for its written criteria.
Can you take GLP-1 medicine after bariatric surgery?
Some people use medicine before or after surgery, for example if weight returns. That is a decision for the surgical and medical team.
References
- 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
- 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
- Weight-loss (Bariatric) Surgery. National Institute of Diabetes and Digestive and Kidney Diseases (NIH). (accessed October 6, 2026) Government page
- Estimate of Bariatric Surgery Numbers, 2011-2023. American Society for Metabolic and Bariatric Surgery. (accessed October 7, 2026) Society statement
- Sjöström L, Narbro K, Sjöström CD, et al.. Effects of Bariatric Surgery on Mortality in Swedish Obese Subjects. New England Journal of Medicine, 2007. doi:10.1056/NEJMoa066254 · PMID 17715408 (accessed October 6, 2026) Other
- National Coverage Determination 100.1: Bariatric Surgery. Centers for Medicare and Medicaid Services. (accessed October 7, 2026) Government page
- Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP). American College of Surgeons. (accessed October 7, 2026) Society statement
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.