A weight-loss surgery is a surgical procedure performed on your stomach (and sometimes the intestine) that can help obese people lose excess weight.

It’s important to note, however, that it is not surgery to remove fat.

Weight-loss surgery can work by:

  • Limiting the amount of food you can eat at one time
  • Changing the way your food is digested so fewer calories and nutrients are absorbed
  • Causing hormone changes that lessen your appetite

In addition to helping people lose weight, weight-loss surgery can help control diabetes and keep prediabetes from getting worse.

Doctors may suggest weight-loss surgery to people with a BMI above 40. Doctors may also suggest weight-loss surgery to people with a BMI of 35 or higher who have a serious health problem because of their weight (such as diabetes, sleep apnea, or high blood pressure). However, weight-loss surgery may also help people at lower levels of obesity (a BMI between 30 and 35) who have diabetes or prediabetes.

Three common types of weight-loss surgery are:

  • Adjustable gastric band (Lap-Band Gastric Banding System, Realize Gastric Band)
  • Sleeve gastrectomy
  • Gastric bypass
Note: Weight-loss surgery is not a quick and easy answer to losing weight and controlling your diabetes or keeping your prediabetes from getting worse. People who have weight-loss surgery must change the way they eat and must get regular exercise. Weight-loss surgery also comes with many risks, which are described below.

Overview of weight-loss surgeries

Adjustable Gastric Band

adjustable-gastric-bandHow does it work? An adjustable gastric band decreases the amount of food you can eat at one time. The band makes you feel full after eating only a small amount.

After having this surgery, eating too much at one time may cause you to vomit.

How is it done? The surgeon puts a small band around the top of your stomach. The band squeezes your stomach to make a small pouch.

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The band is adjustable, and your doctor can make it smaller or wider, depending on how full you feel after eating, how hungry you are, and how much weight you are losing. The band is filled with saltwater and is connected to a tube that leads to a port. The port is placed inside your body just under the skin, and your doctor can change the size of the band by sticking a needle through the skin into the port and adding or removing saltwater.

Is it reversible? It is possible to reverse this type of weight-loss surgery. A surgeon can take the band out, but it may be difficult due to scarring from the first surgery.

Sleeve Gastrectomy

sleeve-gastrectomyHow does it work? A sleeve gastrectomy works in two ways:

  • By decreasing the amount of food you can eat at one time
  • By causing hormone changes that lessen your appetite

How is it done? The surgeon removes most of your stomach, leaving only a narrow tube (or “sleeve”) for food to travel through.

Is it reversible? This type of weight-loss surgery is not reversible.

Gastric Bypass

How does it work? A gastric bypass works in three ways:

  • By decreasing the amount of food you can eat at one time
  • By changing the way calories and nutrients are absorbed from the food you eat
  • By causing hormone changes that lessen your appetite

types of weight-loss surgery - Gastric-bypassAfter having this surgery, eating a lot of carbohydrates (starches), sugar, or fat could cause pain in your belly, cramping, nausea, and diarrhea.

How is it done? The surgeon divides your stomach to make a small pouch. The surgeon then connects the end of the pouch to the middle part of your small intestine. This means that when you eat, the food does not go through the rest of your stomach and the first part of your small intestine.

Is it reversible? This type of weight-loss surgery is not reversible.

Laparoscopic Surgery

These three types of weight-loss surgery (adjustable gastric band, sleeve gastrectomy, and gastric bypass) can be done as laparoscopic surgery.

In laparoscopic surgery, the surgeon uses a tool called a laparoscope — a thin tube with a tiny camera that the surgeon puts through small cuts in your belly along with other small tools to do the surgery. The laparoscope lets the surgeon see inside your body and do the surgery without having to make a big cut, which may help you recover more quickly.

What are the risks of weight-loss surgery?

Weight-loss surgery comes with many risks. Some of these risks can be life threatening.

All weight-loss surgeries come with these risks:

  • Stomach pain, nausea, and vomiting
  • Stomach ulcers
  • Injury to your organs (such as the intestines or stomach)
  • Infection in the surgery wound
  • Bleeding in your belly
  • Blood clots (a clot could travel to your lung, which could be life threatening — a risk with any surgery)

Note: In some cases, people may not lose weight after weight-loss surgery. It is also possible to gain back weight that was lost.

Other possible risks are listed below for each type of weight-loss surgery.

Adjustable gastric band comes with these risks:
  • The band could slip out of place*
  • The band could become embedded in your stomach*
  • Problems with the tube that connects the band to the port
  • Problems with the port

* If this happens, you may need another surgery to fix the band or remove it.

Sleeve gastrectomy comes with these risks:
  • Worsened acid reflux (heartburn)
  • Blockages in your stomach from scar tissue*
  • Leaks from where your stomach was cut*
  • Narrowing of the sleeve created during surgery (symptoms of this include nausea, vomiting, and difficulty swallowing). If this happens, the doctor may need to do a procedure to widen the sleeve.

* You may need another surgery to fix this.

Gastric bypass comes with these risks:
  • Not getting enough vitamins and other nutrients your body needs
  • Blockages in your intestines from scar tissue*
  • Internal hernia (part of your intestine bulges through an opening inside your belly)*
  • Leaks from your intestines where cuts were made during the surgery*
  • Narrowing of the connection between your stomach and intestine (symptoms of this include nausea, vomiting, and difficulty swallowing). If this happens, the doctor may need to do a procedure to widen the connection.

* You may need another surgery to fix this.


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About: This information was provided by the Agency for Healthcare Research and Quality. The summary was prepared by the John M. Eisenberg Center for Clinical Decisions and Communications Science at Baylor College of Medicine, Houston, TX. It was written by Amelia Williamson Smith, MS, Juliet Holder-Haynes, MD, and Michael Fordis, MD People with diabetes or prediabetes and a BMI between 30 and 35 and people who have had weight-loss surgery reviewed this summary.

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