Skip to content

    Bariatric surgical procedures affect weight loss through two fundamental mechanisms -- malabsorption and restriction. Some procedures combine the two:



    Gastric Bypass

    Gastric Banding


    Biliopancreatic Diversion (with or without Duodenal Switch)

    What's involved? Staples partition the stomach below the esophagus to make a small pouch. This pouch connects to the lower small intestine, bypassing the upper segment (duodenum). A band constricts the stomach just below the esophagus, creating a small pouch with a narrow outlet to the larger part of the stomach. The band may be adjustable. Staples and a band divide the stomach in two, creating a small pouch below the esophagus, with a narrow outlet to the larger section of stomach. Removes part of the stomach. The small intestine is cut. One end attaches to the stomach. The bypassed segment of small intestine reconnects near the colon.
    Type Combination Restrictive Restrictive Combination
    How common is this surgery? Most common of weight loss surgery Common -- about 10%-15% of weight loss surgery Rarely done due to lack of sustained/desired weight loss, as well as the high incidence of complications requiring revision (20 to 56 percent). Less common -- about 5% of weight loss surgery
    How much excess weight do people typically lose after surgery?        

    in 1 year

    38% 21% 26% 53%-68%

    in 2 years

    70% 50%-60% 68% 70%-80%
    Average absolute weight loss        

    in 1 year

    96 lbs 67 lbs 71 lbs 114 lbs

    in 2 years

    96 lbs 63 lbs 88 lbs 102 lbs
    How well does it work in the long term?        
    Average percent weight loss 10 years, 25% 10 years, 13% 10 years, 17% 8 years, 60%-70%
    What are the risks of surgery?        
    Death Laparo
    Open Laparo
    Open Laparo
    Open Laparo
    Death Less than 1% Less than 1% Less than 0.1% Less than 1% Less than 1% Less than 1% 1% Less than 1%
    Internal leaking of the bowel or stomach 2% NA 1% 2%
    Internal bleeding 2% Less than 1% Less than 1% Less than 1%
    Repeat surgery 2% 8% 11% 4%
    What percent of people have side effects after surgery?        

    Gastrointestinal symptoms, such as:

    Difficulty swallowing

    Dumping syndrome

    17% 7% 18% 38%
    Any nutrient or vitamin deficiency 17% NA 3% Up to 50%
    Gallstones Up to 36%      
    How long is the average hospital stay for this surgery?        


    2 days 1 day 1 day 3 days


    3 days 4 days 4 days
    What's the average price of the surgery?        


    $30,000 $22,000 $22,000 NA


    $24,000 (average in U.S.) $15,000 (average in U.S.) NA



    WebMD Medical Reference

    Healthy Recipe Finder

    Browse our collection of healthy, delicious recipes, from WebMD and Eating Well magazine.

    Top searches: Chicken, Chocolate, Salad, Desserts, Soup

    Heart Rate Calculator

    Ensure you're exercising hard enough to get a good workout, but not strain your heart.

    While you are exercising, you should count between...