Gastric Sleeve Surgery: Overview

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Gastric sleeve surgery—also known as sleeve gastrectomy—is a type of bariatric (weight loss) surgery. Gastric sleeve surgery involves reducing the size of your stomach so you feel full after eating only a small amount of food. While this operation is an effective means of losing weight, it's not a permanent solution. Patients must be willing and able to commit to lifelong healthy eating and exercise habits to sustain weight loss and avoid complications.

According to the American Society for Metabolic and Bariatric Surgery, gastric sleeve surgery is the most commonly performed bariatric procedure in the United States.

Steps involved in gastric sleeve surgery

What Is Gastric Sleeve Surgery?

Gastric sleeve surgery is an inpatient procedure performed by a bariatric surgeon in a hospital or surgical center under general anesthesia. This scheduled, one- to two-hour surgery may be performed in adults as well as adolescents.

With gastric sleeve surgery, the surgeon removes about 80% of the stomach in order to create a smaller stomach. The new stomach is tubular in shape and about the size of a banana. With this reduction, patients feel full for several hours after eating just a little amount of food—thus, reducing their overall intake.

Besides making a smaller stomach, gastric sleeve surgery removes the stomach cells that normally produce the hunger hormone ghrelin. This decrease in hormone production means patients often experience a decrease in appetite, which can further contribute to weight loss.

Various Surgical Techniques

The gastric sleeve procedure is usually done laparoscopically, using minimally invasive techniques. Less commonly, the surgery is open, which means that the surgeon makes a large incision in the patient's abdomen to access the stomach.

When compared to gastric bypass surgery, another popular weight loss procedure, gastric sleeve surgery is associated with lower risks and is technically easier to perform. Gastric sleeve surgery is also not considered as extreme by patients, as it is only a restrictive procedure and does not involve reducing nutrient absorption in the small intestines.

Criteria and Contraindications

The indications for undergoing weight loss surgery, including gastric sleeve surgery, are:

BMI is a dated, flawed measure. It does not take into account factors such as body composition, ethnicity, sex, race, and age. 
Even though it is a biased measure, BMI is still widely used in the medical community because it’s an inexpensive and quick way to analyze a person’s potential health status and outcomes.

An exception to the above criteria is that Asian patients who have poorly controlled type 2 diabetes and a BMI as low as 27.5 may be considered for surgery.

This exception exists because, when compared to whites, Asians are more likely to store fat in their abdomen, as opposed to peripherally (e.g, in their buttocks, hips, and thighs). With this abdominal fat accumulation, they have an increased risk of insulin resistance and cardiovascular disease, even at relatively low BMIs.

Absolute contraindications to undergoing gastric sleeve surgery include:

Relative contraindications to undergoing gastric sleeve surgery include Barrett's esophagus, gastroesophageal reflux disease (GERD), and a large hiatal hernia.

Potential Risks

While gastric sleeve surgery is less risky than other bariatric surgeries, there are potential side effects and complications that can happen in the days or even years after the procedure.

In addition to the known risks of anesthesia and the general risks of surgery, gastric sleeve surgery is associated with these specific risks:

  • Bleeding, usually of the staple line (where the stomach has been divided)
  • Stricture formation (narrowing) within the new tubular stomach can make it difficult for food and fluids to pass through
  • Gastric leak (when stomach contents leak into the abdominal cavity)
  • An abdominal abscess (collection of pus)
  • Wound infection
  • Nutritional deficiency due to a decrease in food consumption
  • GERD
  • Weight regain (often due to changes in eating habits)

Purpose of Gastric Sleeve Surgery

The purpose of gastric sleeve surgery is weight loss, as well as reversing or improving health conditions that may be associated with obesity.

Examples of obesity-related conditions include:

If you meet the criteria for gastric sleeve surgery, you will need to undergo several tests and assessments to be fully cleared for the procedure.

These tests include:

  • A medical history and physical examination to evaluate or screen for conditions that may cause problems before or after surgery (for example, obstructive sleep apnea)
  • Various pre-operative laboratory studies, such as a complete blood count, liver function test, and hemoglobin A1C)
  • A nutritional assessment to evaluate for vitamin and mineral deficiencies (e.g., vitamin D, iron, and vitamin B12)
  • An anesthesia assessment to access risks for general anesthesia
  • A psychological and cognitive evaluation to determine if you are ready to undergo a procedure that will ultimately require significant lifestyle changes
  • A primary care physician consultation to ensure the completion of all age-appropriate cancer screenings
  • Pregnancy counseling for female patients in their childbearing years

Lastly, a gastroenterology consultation may be required to evaluate for conditions that may ultimately delay or be a contraindication to surgery (e.g., hiatal hernia, ulcer, or mass).

How to Prepare

Once your surgery is scheduled, your surgeon will give you instructions to help you prepare.

These instructions may include:

  • Engaging in several bariatric pre-surgical lifestyle classes
  • Consuming a liquid-only diet for one to two weeks before your surgery (this may depend on factors like your current BMI going into surgery and surgeon preference)
  • Stopping smoking for three months prior to surgery
  • Avoiding caffeine for at least one month prior to surgery
  • Stopping certain medications for an advised period of time before surgery
  • Showering the night before the surgery using a special type of antibacterial soap
  • Refraining from eating or drinking anything after midnight on the eve of your surgery
  • Packing personal items, like a comb and toothbrush, for your hospital stay

What to Expect on the Day of Surgery

On the day of your gastric sleeve surgery, you can expect the following steps:

  • Upon arrival at the hospital, you will go to a pre-operative room where you will change into a hospital gown and have an IV catheter placed in a vein in your arm.
  • Once in the operating room, you will be given anesthesia to put you to sleep.
  • The surgeon will make at five or six tiny incisions in the abdomen through which a camera and long, thin surgical instruments will be inserted.
  • Using these instruments, the surgeon will remove the majority of the stomach through one of the incisions. This will leave a portion of the stomach that connects the esophagus to the first part of the intestine called the duodenum.
  • The incision line where the stomach was removed will then be closed with staples. The suture line will be carefully checked to make sure that it is not leaking.
  • The surgeon will then remove the instruments and close the rest of the incision sites with absorbable sutures and sterile tape. 
  • Anesthesia will be stopped and you will be taken to a recovery room where you will wake up.


Once you wake up in the recovery room, it's normal to feel groggy and experience some nausea, vomiting, and pain. Rest assured that a nurse can give you pain and anti-nausea medications to help ease your symptoms.

Usually, you will be moved from the recovery room to a hospital room after a few hours. You can expect to stay for one to two nights.

You will be closely monitored for complications like bleeding and infection. You will also be encouraged to start walking as soon as possible to avoid developing blood clots in your legs.

Once you are tolerating a clear liquid diet well (which usually begins the morning after surgery) and you have no signs of complications, you will likely be discharged home and given various instructions to follow.

Some of these instructions may include:

  • Seeing a nutritionist regularly: You will slowly advance your diet over a period of several weeks from liquids to puréed foods to soft foods to solids.
  • Drinking water regularly to stay hydrated
  • Returning to work one to two weeks after surgery (if it involves mild activity)
  • Taking any medications as directed: All medications will need to be crushed, or taken in liquid form for the first two weeks after surgery.
  • Keeping your incision sites clean and dry
  • Avoiding strenuous activity for three to six weeks after surgery

Long-Term Care

The vast majority of patients lose a significant amount of weight after gastric sleeve surgery. The key is keeping the weight off. Fortunately, research has found that by the five-year post-surgery mark, the average patient is down about 60% of their excess body weight.

Still, some patients may require revision surgery (usually a revision sleeve gastrectomy or conversion to a Roux-en-Y gastric bypass) because of insufficient weight loss or weight regain. The development of severe GERD from gastric sleeve surgery is another indication for revision surgery.

In the end, gastric sleeve surgery is not a quick fix for losing weight. Patients must see their surgeon and a bariatric registered dietitian regularly and strictly adhere to a diet and exercise regimen after surgery.

This regimen includes:

  • Adhering to a healthy diet that is rich in protein, fruits, and vegetables
  • Limiting processed foods, snacks, and desserts
  • Exercising regularly
  • Daily tracking of food intake using an online diary or food journal
  • Taking various vitamins (complete multivitamin, calcium, vitamin D, iron, vitamin C, and vitamin B12)

Keep in mind that there are significant emotional issues that can accompany any type of weight loss procedure as well. For people who use eating as a coping mechanism, finding a new way to adapt and manage stress without food can be challenging.

It's important to find healthy outlets for stress, such as exercise or making quality time for yourself. Open and clear communication with friends and family can also be useful, as can a bariatric support group. In some instances, seeing a therapist or psychologist who specializes in bariatric surgery may be warranted.

A Word From Verywell

Long-term success from gastric sleeve surgery will depend entirely on your willingness to create new habits and stop behaviors that encourage obesity. The most successful individuals create a system of accountability in their lives by working closely with friends, relatives, and professional healthcare providers to maintain good habits day to day.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading

By Jennifer Whitlock, RN, MSN, FN
Jennifer Whitlock, RN, MSN, FNP-C, is a board-certified family nurse practitioner. She has experience in primary care and hospital medicine.