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How does bariatric surgery affect weight loss?


Bariatric surgery produces weight loss primarily by limiting how much the stomach can hold.
This type of surgery also delays emptying of the stomach (gastric pouch).

Surgical procedures are often combined with bypass procedures to limit calorie and nutrient absorption and may lead to altered food choices. Two ways surgery promotes weight loss are:
  • By decreasing food intake. Gastric banding and gastric bypass are operations that limit the amount of food the stomach can hold by closing off or removing parts of the stomach.    

  • By causing food to be poorly digested and absorbed. In gastric bypass procedures, the surgeon makes a direct connection from the stomach to a lower segment of the small intestine, bypassing the upper section of the small intestine.