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What is the difference between gastric sleeve and gastric bypass surgery?

yael cooperman

Reviewed by Yael Cooperman, MD, written by Cale Li, MD

Last updated: Apr 30, 2021
6 min read


If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.

Gastric bypass and gastric sleeve are the two most common weight loss procedures done each year. 

Gastric bypass surgery reshapes the stomach and rearranges the digestive system’s anatomy, while gastric sleeve only reshapes the stomach. Both surgeries have been proven to be effective for weight loss, but is one better than the other? 


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Lose 15% of your body weight in one year on average


weight loss

Lose 15% of your body weight in one year on average

Gastric sleeve vs. gastric bypass surgery

Gastric bypass and gastric sleeve surgeries are similar in that each procedure works for weight loss, and both involve reshaping the stomach to hold less food. Gastric bypass is more complex as it involves rearranging part of the digestive tract, which we’ll get into later. 

The procedures are often done laparoscopically, a minimally-invasive way of performing surgery that uses a tiny camera. The benefits of laparoscopic surgery are shorter hospital stays and lower rates of complications like surgical site infections and hernias (Reoch, 2011).

While both surgeries are effective for weight loss, people lose more weight after gastric bypass. Since gastric bypass is a more complicated surgery, there’s a slightly higher risk of surgical complications than gastric sleeve, although the rate of life-threatening complications is the same between both (Lager, 2017).

Here’s some more helpful information about both weight loss procedures to help you get started. 

Gastric bypass surgery

Gastric bypass accounts for around 70% of the bariatric surgeries performed in the United States every year. 

To understand how the procedure works, you need to know the route food travels. It enters the first part of your small intestine called the duodenum and passes through two more parts before hitting the large intestine. 

In gastric bypass surgery, the stomach is reshaped into a smaller pouch. The pouch is then disconnected from the first part of your small intestine and reattached to the second part. The remaining part of your stomach stays put as a separate pouch.

This setup allows food to bypass a significant portion of the digestive system, so fewer nutrients are absorbed. Coupled with having a smaller stomach, this leaves you feeling full after eating less (Mitchell, 2020). 

After bypass surgery, people generally lost about 31% of their total body weight in the first three years. After 10 years, they maintained nearly all of that weight loss (Maciejewski, 2016). 

Gastric sleeve surgery 

Gastric sleeve surgery, also called sleeve gastrectomy, is the second most commonly performed weight loss procedure. 

Around 75% of the stomach is removed during the procedure. The remaining portion is shaped into a tube or sleeve. Like gastric bypass, the stomach now holds less food, and you feel full after eating less. Unlike gastric bypass, there is no rearranging of the stomach and small intestine (Mitchell, 2020). 

Within the first three years afterward, people generally lost around 25% of their total body weight. Some weight regain is to be expected, and seven years out, people kept off 16% of their original weight (Sepúlveda, 2017).

Is one surgery safer than the other? 

Both procedures are relatively safe, although gastric bypass has a higher rate of complications.

All surgical procedures can carry risks, but in general, laparoscopic surgery (in which surgical devices are inserted through small, coin-sized incisions) is fraught with fewer problems than open surgeries with larger incisions.

Since gastric bypass and gastric sleeve are done via laparoscopic surgery, the complication rate is low—especially compared to open surgery (Stahl, 2020). 

In a study comparing the two procedures, gastric bypass had more adverse side effects, such as infections at the surgical site and non-life-threatening bleeding. More severe complications, like blockages in the digestive tract or leakage from areas where the digestive tract was stitched, are rare with both procedures (Lager, 2017). 

Most people don’t stay in the hospital very long after surgery and usually go home within two to five days. In a study looking at recovery times following gastric bypass, most patients were safely discharged the day after (Hahl, 2016). 

Factors that determine how long you stay in the hospital include whether you can tolerate a liquid diet to go home on, the amount of pain you have, and if complications occur. 

Who qualifies for gastric bypass or sleeve?

Not everyone should undergo gastric bypass or sleeve surgeries. Getting a consultation with a surgeon is an important first step to determine if you’re a good fit for surgery. While there aren’t hard and fast requirements for eligibility, medical professionals generally follow these criteria (ASMBS, 2021): 

  • Having a body mass index (BMI) equal to or greater than 40—roughly 100 pounds overweight. BMI or body mass index is a way to measure body fat based on height and weight. A BMI greater than or equal to 25 is considered in the overweight category. Greater than 30 falls in the obese range.
  • People with a BMI equal to or greater than 35 along with an obesity-related illness like high blood pressure, diabetes, sleep apnea, or high cholesterol.
  • For people with a BMI of less than 35 who also have type 2 diabetes, the decision can be made on a case-by-case basis. In a recent study, gastric bypass led to more remissions in type 2 diabetes, fewer relapses of diabetes, and better overall sugar control than gastric sleeve (McTigue, 2020).

What does recovery look like after surgery?

The recovery period can vary from person to person, as everyone heals at their own pace. Life after gastric surgery will require some adjustment. 

You will probably go home from the hospital only able to only drink liquids, and that’s okay. Continue to on a liquid diet until you feel comfortable eating soft, solid foods. A healthcare provider will follow up with you at regular clinic visits to monitor your dietary progress. 

Other things to be mindful of following surgery include what to eat, nutritional needs, and potential complications.

Nutritional needs

After surgery, your body won’t absorb nutrients the same way as before. If you’re having trouble absorbing specific vitamins, a healthcare professional can guide you on what supplements you will need. Ones you might need after gastric surgery include folic acid, vitamin B12, vitamin D, and iron

Nutritional deficiencies can occur following either procedure, although deficiencies are more common after gastric bypass.

Dumping syndrome 

When adjusting to the new size of your stomach, you may need to make some dietary changes. One of the complications that can happen after gastric bypass is something called dumping syndrome. 

Dumping syndrome happens when food moves too rapidly from the stomach to the rest of the digestive system. Common signs include dizziness, nausea, sweating, diarrhea, and abdominal pain (Ma, 2015). It’s an expected side effect of gastric bypass and less common following gastric sleeve. 

The recommended treatment for dumping syndrome is diet modification to avoid foods that cause symptoms—most often simple carbohydrates, like refined sugar or high fructose corn syrup. 

Opt for more complex sugars, such as those found in vegetables, fruits, and whole grains. Eating foods with high fiber can also help, as fiber prolongs the transit time of food through your digestive tract. Dumping syndrome usually disappears after a year for most people (Ma, 2015).

Overall, gastric bypass and gastric sleeve are both relatively safe procedures. Gastric bypass is associated with more weight loss and better diabetes control but carries more complication risks than gastric sleeve.

The good news is that with either procedure people reported a marked improvement in their quality of life within the first year. This includes improvements in physical function, a better social life, and more independence in daily living activities like bathing and dressing (Major, 2015). 

Gastric surgery isn’t for everyone, but for some, it’s an effective weight loss treatment. Whether gastric sleeve or gastric bypass is better for you is a decision that should be made between you and a trusted healthcare provider. 


  1. American Society for Metabolic and Bariatric Surgery (ASMBS). (2021). Who is a Candidate for Bariatric Surgery? ASMBS. Retrieved on April 16, 2021 from https://asmbs.org/patients/who-is-a-candidate-for-bariatric-surgery
  2. Hahl, T., Peromaa-Haavisto, P., Tarkiainen, P., Knutar, O., & Victorzon, M. (2016). Outcome of Laparoscopic Gastric Bypass (LRYGB) with a Program for Enhanced Recovery After Surgery (ERAS). Obesity Surgery, 26(3), 505–511. doi: 10.1007/s11695-015-1799-z. Retrieved from https://pubmed.ncbi.nlm.nih.gov/26205214/
  3. Lager, C. J., Esfandiari, N. H., Subauste, A. R., Kraftson, A. T., Brown, M. B., Cassidy, R. B., Nay, C. K., Lockwood, A. L., Varban, O. A., & Oral, E. A. (2017). Roux-En-Y Gastric Bypass Vs. Sleeve Gastrectomy: Balancing the Risks of Surgery with the Benefits of Weight Loss. Obesity Surgery, 27(1), 154–161. doi: 10.1007/s11695-016-2265-2. Retrieved from https://pubmed.ncbi.nlm.nih.gov/27342739/
  4. Ma, I. T., & Madura, J. A., 2nd (2015). Gastrointestinal Complications After Bariatric Surgery. Gastroenterology & Hepatology, 11(8), 526–535. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4843041/
  5. Maciejewski, M. L., Arterburn, D. E., Van Scoyoc, L., Smith, V. A., Yancy, W. S., Jr, Weidenbacher, H. J., Livingston, E. H., & Olsen, M. K. (2016). Bariatric Surgery and Long-term Durability of Weight Loss. JAMA Surgery, 151(11), 1046–1055. doi: 10.1001/jamasurg.2016.2317. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5112115/
  6. Major, P., Matłok, M., Pędziwiatr, M., Migaczewski, M., Budzyński, P., Stanek, M., Kisielewski, M., Natkaniec, M., & Budzyński, A. (2015). Quality of Life After Bariatric Surgery. Obesity Surgery, 25(9), 1703–1710. doi: 10.1007/s11695-015-1601-2. Retrieved from https://pubmed.ncbi.nlm.nih.gov/25676156/
  7. McTigue, K. M., Wellman, R., Nauman, E., Anau, J., Coley, R. Y., Odor, A., et al. (2020). Comparing the 5-Year Diabetes Outcomes of Sleeve Gastrectomy and Gastric Bypass: The National Patient-Centered Clinical Research Network (PCORNet) Bariatric Study. JAMA Surgery, 155(5), e200087. doi: 10.1001/jamasurg.2020.0087. Retrieved from https://pubmed.ncbi.nlm.nih.gov/32129809/
  8. Mitchell, B. G., & Gupta, N. (2020). Roux-en-Y Gastric Bypass. StatPearls. StatPearls Publishing. Retrieved March 2, 2021 from https://pubmed.ncbi.nlm.nih.gov/31985950/
  9. Reoch, J., Mottillo, S., Shimony, A., Filion, K. B., Christou, N. V., Joseph, L., Poirier, P., & Eisenberg, M. J. (2011). Safety of laparoscopic vs open bariatric surgery: a systematic review and meta-analysis. Archives of Surgery, 146(11), 1314–1322. doi: 10.1001/archsurg.2011.270. Retrieved from https://pubmed.ncbi.nlm.nih.gov/22106325/
  10. Sepúlveda, M., Alamo, M., Saba, J., Astorga, C., Lynch, R., & Guzmán, H. (2017). Long-term weight loss in laparoscopic sleeve gastrectomy. Surgery for Obesity and Related Diseases, 13(10), 1676–1681. doi: 10.1016/j.soard.2017.07.017. Retrieved from https://pubmed.ncbi.nlm.nih.gov/28807556/
  11. Stahl JM, Malhotra S. (2020) Obesity Surgery Indications And Contraindications. StatPearls. Retrieved on March 6, 2020 from https://www.ncbi.nlm.nih.gov/books/NBK513285/#_NBK513285_pubdet_

Yael Cooperman is a physician and works as a Senior Manager, Medical Content & Education at Ro.