What is weight loss (bariatric) surgery?

Bariatric surgery is surgery to help you lose weight. This type of surgery is only used for people who are very overweight and have not been able to lose weight with diet and exercise.

This surgery makes the stomach smaller. Some types of surgery also change the connection between your stomach and intestines.

Having weight-loss surgery is a big step. After surgery, you'll need to make new, lifelong changes in how you eat and drink.

This type of surgery may be considered if your body mass index (BMI) is at least 40, or if it's at least 35 and you have other weight-related health problems. If your BMI is 35 or higher, surgery may be done if you have tried for at least 6 months to lose weight.

Depending on whether your weight-loss surgery is to make your stomach smaller or to change the path of your intestine, your doctor will perform one of these procedures:

Adjustable gastric banding.

The doctor wraps a band around the upper part of the stomach to make the stomach smaller.

Gastric sleeve.

The doctor removes more than half of your stomach, leaving a thin vertical sleeve, or tube.

Gastric bypass.

The doctor uses a small part of your stomach to create a smaller stomach. This is connected to the middle part of the small intestine. Food skips (bypasses) the rest of the stomach and part of the small intestine. This surgery is called a Roux-en-Y (say "roo-en-why") gastric bypass.

Depending on the type of surgery, most people lose at least a third of their extra weight after surgery. Some people lose almost all of their extra weight. Weight loss varies with the type of surgery. It also depends on how closely people follow their doctor's advice for lifestyle changes, checkups, and counseling.

Research shows that people who have gastric bypass surgery lose more total weight than those who have gastric sleeve or gastric banding surgery. But those who have gastric bypass surgery have more complications right after surgery.

Having weight-loss surgery is a big step. You can prepare for surgery by having a plan. Your plan may include your goals for losing weight and how to make changes in your diet, activity, and lifestyle to help raise your chances of success.

One way to prepare for surgery is to think about your goal or reason why you want to reach a healthy weight. Do you want to lower your blood pressure, cholesterol, or blood sugar? Do you want to be able to sleep better, play with your kids, or walk around the block? Having a reason can help you stay with your plan and meet your goals.

You'll have a weight loss team that you can talk to about your plans and goals. The team will help you get ready for surgery. After surgery, the team will help you adjust to new ways of eating and changes to your body.