Skip to content

Weight Loss Surgery Health Center

What Happens During Weight Loss Surgery

Font Size
A
A
A

Exactly what your surgeon will do when you get weight loss surgery depends on what type of surgery you're getting. Weight loss surgery works in three basic ways:

  • Restricting how much food your stomach can hold at any time. This is "restrictive" weight loss surgery.
  • Preventing your digestive system from absorbing all the nutrition in the food you eat. This is "malabsorptive" surgery.
  • A combination of these two ways

Here's what each procedure involves.

Recommended Related to Weight Loss Surgery

Comparing Your Weight Loss Surgery Options

    Gastric Bypass Gastric Banding Gastroplasty 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...

Read the Comparing Your Weight Loss Surgery Options article > >

Restrictive Weight Loss Surgery

The two purely restrictive types of weight loss surgery are called gastric banding and vertical sleeve gastrectomy.

Both operations make less room in the stomach for food right after it's swallowed.

The surgeon uses a small part of your stomach to make a pouch at the end of your esophagus (the tube connecting your mouth to your stomach). This pouch holds only about half an ounce -- roughly the space in a shot glass. It fills up quickly and empties slowly, through a narrow opening to the larger part of the stomach.

Gastric banding involves placing a band around the top end of the stomach. There are two approved gastric banding devices and procedures approved in the U.S. -- LAP-BAND and the Realize band.

Vertical sleeve gastrectomy involves removing about 75% of the stomach. What remains of the stomach is a narrow tube or sleeve, which connects to the intestines.

Malabsorptive Weight Loss Surgery: Gastric Bypass and Biliopancreatic Bypass

Gastric bypass surgery also involves creating a small pouch. The difference between gastric bypass and gastric banding is that food doesn't pass through the pouch to be further digested in the larger part of the stomach.

Instead, the pouch empties directly into the small intestine. To make this work, the small intestine is severed. The surgeon connects one end of it to an opening in the new stomach pouch.

After this surgery, when you eat, food bypasses most of your stomach and the first part of your small intestines. That makes this surgery both restrictive and malabsorptive.

Surgeons rarely do weight loss surgery that's only malabsorptive. One exception is a surgery that removes much of the stomach. That surgery is called a biliopancreatic diversion with a duodenal switch.

Deciding on Weight Loss Surgery

Before you have weight loss surgery, you'll go through an evaluation process that includes counseling and various tests.

All types of weight loss surgery have pros and cons. Those that involve more cutting, sewing, and rearranging things inside of you may yield slightly better results, but they also may come with more side effects.

WebMD Medical Reference

Reviewed by Melinda Ratini, DO, MS on September 10, 2014

Today on WebMD

mid section view of a woman measuring her waist
Procedures to choose from.
stomach
What to expect.
 
Doctor Examining Male Patient With Hip Pain
Common questions answered.
Woman weighing self after drinking water
Get the facts.
 
calculate your bmi
Tool
Healthy woman eating for a healthy lifestyle
Quiz
 
Obesity What Does It Mean
Article
clams
Quiz
 
Types Of Weight Loss Surgery
Medical Reference
woman eating apple
Article
 
BHC Eating and Nutrition Healthcheck
Evaluator
Plastic Surgery After Weight Loss
Article