Gastric sleeve surgery is a surgical weight loss procedure that permanently reduces the size of the stomach. A doctor may recommend it for people with obesity who have not found other weight loss strategies effective.

During gastric sleeve surgery, a surgeon removes about 80% of the stomach. This limits the amount of food the individual can consume, helping them lose weight in the long term.

Although this operation can help people with obesity, it is a significant procedure that carries risks. Additionally, people can only maintain the weight loss by following a sustainable diet and exercise plan.

This article explains how gastric sleeve surgery works and why experts recommend it. It also discusses the long-term changes that people will need to make for it to be successful.

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Gastric sleeve surgery is one of several bariatric surgical procedures for people with clinically severe obesity. Doctors consider obesity to be clinically severe if the person has a body mass index (BMI) of 40 or higher. However, people with a BMI of 35–39.9 may also be candidates if they have at least one serious comorbidity.

Gastric sleeve surgery is the most common form of weight loss surgery in the United States. According to the American Society for Metabolic and Bariatric Surgery (ASMBS), it accounted for 59.4% of bariatric procedures in 2019.

The procedure permanently reduces the size of the stomach. After surgery, the size of the stomach will be about 20% of its original size.

This reduced size limits how much food and liquid a person can ingest, helping them feel fuller sooner. It also limits hunger signals over time because it removes the part of the stomach that produces the hunger hormone ghrelin.

A doctor may advise a person to have gastric sleeve surgery if they:

  • have a BMI over 40
  • have a BMI of 35–40 as well as an underlying health condition, such as sleep apnea, hypertension, or type 2 diabetes
  • have tried other weight loss methods and found them ineffective

Gastric sleeve surgery is an invasive procedure that requires mental and physical preparation. A person will also need to factor in several weeks or months of recovery.

Before surgery

Prior to having the procedure, candidates for surgery will need to enroll in a bariatric surgery education program. This helps them get ready for the operation and may involve losing weight, stopping certain medications, and quitting smoking, if applicable.

Individuals will also receive nutritional counseling to help them stick to a well-balanced diet after surgery.

In addition to a psychological evaluation, a doctor will carry out blood tests, physical examinations, and imaging studies of the person’s stomach. They may also perform an upper endoscopy to check the gastrointestinal tract for any abnormalities.

During surgery

A person will need general anesthesia for the surgery. This will put them to sleep, so they will have no memory of the operation.

During the procedure, a surgeon will use laparoscopy by making several small incisions in the abdomen and inserting surgical tools and scopes. Using these tools, the surgeon will isolate the stomach and use surgical staples to remove up to 80% of it. This leaves a narrow vertical “sleeve.”

The surgeon will remove the rest of the stomach through one of the incisions.

After surgery

Usually, people follow a liquid diet for 1–2 weeks. They will gradually introduce purees and then soft foods, before finally including regular solid foods in the diet.

A healthcare team will work with the individual to provide advice on meal nutrition and size while the stomach heals.

Meals after surgery will be small, and people should focus on chewing their foods thoroughly. They may also need to take supplements to ensure that they are getting adequate vitamins and minerals, as these can be harder to obtain through smaller meals.

People may also need to have regular blood tests to check their iron, blood glucose, calcium, and vitamin D levels. Heartburn medication may sometimes be necessary to reduce stomach acid.

Learn more about nutrition after gastric sleeve surgery.

Gastric bypass is another common bariatric surgery. It involves dividing the stomach into two sections. The smaller part of the stomach becomes the new stomach, and the larger portion no longer stores or digests food. This helps people lose weight by decreasing hunger, increasing fullness, and reducing hunger hormones.

According to the ASMBS, the procedure is technically more complex than gastric sleeve and results in more vitamin and mineral deficiencies. In addition, recovery from the gastric sleeve procedure is faster and carries a lower risk of complications. For this reason, it is generally a preferable option.

However, gastric bypass typically leads to more significant and faster weight loss.

It can take 4–6 weeks to resume normal activities after weight loss surgery.

However, even after a person has physically healed from the surgery, they will need to stick to certain recovery practices. A doctor or dietitian will recommend long-term dietary and lifestyle changes to sustain healthy weight loss.

Their recommendations may include:

  • Diet: People should drink plenty of water, follow the guidelines on when to return to solid foods, and eat small portions. They should also avoid foods with high levels of starch and sugar and opt for high protein foods to prevent weakness and muscle loss.
  • Vitamins: It will be necessary to take vitamin supplements for life. These will typically include a multivitamin, vitamin B12, calcium, vitamin D, and iron.
  • Exercise: A healthcare team will recommend daily moderate exercise of about 30 minutes. This can help the body recover faster and maintain weight loss.
  • Smoking and alcohol: Medical professionals advise that people should continue to avoid smoking after surgery. They will also likely recommend avoiding alcohol after surgery, as this can have severe consequences.
  • Pregnancy: Generally, people should avoid getting pregnant for 12–18 months after weight loss surgery.

Any weight loss surgery, including gastric sleeve surgery, is a major operation. However, the risks of severe complications and death are relatively rare. Research suggests that the fatality rate is close to 1 in 600.

Other risks and complications may include:

  • Blood clots: Surgery can increase the risk of blood clots in the lower legs or lungs.
  • Infection: Wounds may become infected during healing, causing pain and swelling.
  • Leakage: Food or liquid may sometimes leak out of the stomach, which can cause a serious infection.
  • Blocked gut: Scarring from surgery may cause the gut to become blocked, causing vomiting and pain.
  • Malnutrition: Not having enough vitamins and minerals can cause malnutrition.
  • Gallstones: It is common to develop gallstones in the first 1–2 years after surgery.

Although weight loss surgery results in an improvement in mental health for most people, it may negatively affect others. According to a 2019 systematic review, there is a small but significant increase in suicide and self-harm after surgery. Possible reasons for this include previously undiagnosed mental health conditions and the stress of surgery.

For this reason, doctors ask people to have a mental health screening before they decide to undergo surgery.

In the U.S., the average cost of weight loss surgery is typically in the range of $17,000 to $26,000. Insurance companies will usually cover most of the cost, but the extent of coverage depends on a person’s plan, so they should contact their insurance provider to check the details.

Many insurance companies will require people to be on a weight loss program before surgery. This usually lasts 2–3 weeks, but some may be up to 6 months.

Learn about Medicare coverage for gastric sleeve surgery.

Gastric sleeve surgery is a major weight loss operation that removes up to 80% of the stomach. It is one of the most common forms of bariatric surgery in the U.S.

People undergoing the procedure will need to enroll in a program that may include counseling, weight loss, and nutritional education. Recovery may take up to 6 weeks, and people will have to take certain medications and supplements for life.