Bariatric Surgery: Everything You Need to Know

Also Known as Weight-Loss Surgery

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Bariatric surgery (a.k.a. weight-loss surgery) is part of a multidisciplinary weight loss program that includes healthy eating, exercise, and treatment of conditions like type 2 diabetes or thyroid disease.

There are several bariatric surgeries—gastric bypass, gastric banding, and others—all of which have the same end goal: to reduce the amount of food your body can absorb in order to promote weight loss. Bariatric surgery is a major medical procedure used to help you avoid health complications of obesity, not for cosmetic reasons.

This article will provide a complete overview of bariatric surgery—the types, risks, why it's done, and what to expect.

Surgeons performing gastric bypass surgery
herjua / Getty Images

What Is Bariatric Surgery?

Bariatric surgery reduces the amount of food you can eat and absorb by shrinking the stomach. There are several ways this can be done, including removing part of the stomach, placing a band around the stomach, or relocating the opening between the stomach and the small intestine.

This surgery can be done as a laparotomy (open abdominal procedure with a large incision) or laparoscopically (minimally invasive procedure using tools inserted through small incisions).

General anesthesia is required for pain control during a bariatric operation. You may need to stay overnight in the hospital for several days after the surgery.

Procedure Types

You may be a candidate for one or more bariatric surgeries. A healthcare provider will make a recommendation as to the one they think is best for you depending on your overall health, the amount of weight you need to lose, and other factors.

  • Gastric balloon: This involves the insertion of a deflated balloon through the mouth and into the stomach using a flexible scope called an endoscope. Once positioned, the balloon is inflated to reduce the space within the stomach. This is a temporary procedure and the balloon is later removed (usually within six months).
  • Adjustable gastric banding (lap band): Gastric banding involves the placement of a permanent silicone band around the stomach. The band reduces the size of the stomach without cutting away any portion of it. This procedure is usually performed laparoscopically. A small port is placed directly underneath the skin so the band can be adjusted.
  • Sleeve gastrectomy: Gastric sleeve surgery is the removal of a portion of the stomach, resulting in a reduction of the stomach's size. After this procedure, typically performed laparoscopically, the remaining stomach is shaped like a sleeve.
  • Gastric bypass: Gastric bypass surgery is the detachment of the opening of the small intestine from the lower part of the stomach and its reattachment to the upper part of the stomach. This decreases the amount of food the stomach can hold, and more importantly, decreases the time that the food spends in the small intestine, limiting how much is absorbed. The most common gastric bypass procedure, called the Roux-en-Y bypass, is typically performed laparoscopically and involves the cutting away of a portion of the stomach in addition to the bypass.

Although some people still think of bariatric surgery as "stomach stapling," the use of surgical staples (referred to as vertical banded gastroplasty or the Mason procedure) has not been employed since the 1980s and is no longer offered for weight loss surgery.


Bariatric surgery is a major procedure. You might not be a candidate for this surgery if you have a severe heart or lung disease that could make it risky for you to have surgery and general anesthesia.

A history of multiple abdominal surgeries can complicate surgery if issues like adhesions (scar tissue) have developed.

Sometimes excess weight can be caused by factors such as medication or medical conditions. And eating disorders can be associated with obesity. In these situations, bariatric surgery might not be effective, and other treatments would be considered instead.

Potential Risks

In addition to the risks of general anesthesia and abdominal surgery, there are a number of potential adverse effects specific to bariatric surgery:

  • Bleeding or perforation of the stomach or intestines: A perforation is when a hole develops through the wall of the gut. These are life-threatening emergencies that require immediate intervention. Such complications are more likely to occur after procedures that involve cutting away sections of the stomach.
  • Bowel obstruction: This is most often caused by an internal hernia in which the small intestine slips into the opening created by the surgery. This can occur weeks or years after the surgery and cause serious bowel damage.
  • Malnutrition, dumping syndrome, and adrenal failure: Severe weight loss often occurs in the months after bariatric surgery, leading to these issues. While they can resolve over time, medical treatment is typically required.
  • Permanent nutrient deficiency: This requires ongoing nutritional supplementation. Unhealthy weight loss and malnutrition can occur after any type of bariatric procedure, but it is less likely after gastric banding than the other types.
  • Incisional hernia or adhesions can form after bariatric surgery, and this may cause pain or bowel obstruction later on.
  • Gastrointestinal issues like gastrointestinal reflux disease (GERD), gallstones, and pancreatitis can occur due to the disruption of the normal production and release of enzymes in the gastrointestinal system.
  • Emotional issues, such as binge eating and depression, generally improve after bariatric surgery. But it is possible for these issues to worsen or newly emerge after surgery as well.

While not a risk of any bariatric procedure itself, it's important to remember that this kind of surgery does not guarantee permanent weight loss. You run the risk of gaining weight after your procedure or losing and then regaining weight if you have a high-calorie diet.

Pros and Cons by Procedure

These procedures vary in some significant ways. For example, some are riskier and have more potential negative health effects than others.

  Balloon Band Gastrectomy Bypass
Risk of surgical complications Low Low Moderate Moderate
Recovery time Weeks Weeks 4-6 weeks 4-6 weeks
Amount of weight loss Moderate Moderate High High
Risk of malnutrition  Low Low High High
Likelihood of regaining weight High High Low Low
Reversible? Yes Yes No No

Purpose of Bariatric Surgery

Bariatric surgery is intended to reduce the number of calories absorbed by the body to promote weight loss and reverse/prevent complications of obesity, including:

Some of the late-stage complications of these conditions can complicate bariatric surgery, so the procedure is generally safer before severe health consequences of obesity arise.

Weight-loss surgery shrinks the stomach and/or restructures the opening of the stomach to reduce the amount of food you can eat. Usually, the surgery makes overeating uncomfortable, which promotes eating less. But you also have to maintain a healthy diet that is low in calories, rich in nutrients, and that doesn't lead to excessive bloating or malabsorption.

Early interventions for managing excess weight may include diets, structured exercise programs, and intensive behavioral therapies to target and change unhealthy eating habits. It is when these non-surgical strategies are not effective that bariatric surgery may be considered.

You may be a candidate for weight-loss surgery if you:

  • Have a body mass index (BMI) greater than or equal to 40
  • Are more than 100 pounds overweight
  • Have a BMI of 35 or more with complications of obesity

As you discuss the possibility of surgery with a healthcare provider, you will talk about the non-surgical methods you have already tried, as well as a realistic plan for lifestyle interventions that you should work on before deciding to have surgery.

Furthermore, health insurance payers sometimes require documentation of the health consequences of obesity and/or a certain amount of time working with a nutritionist or fitness trainer before they'll pay for weight-loss surgery.

You will also have a discussion with a healthcare provider about your attitude toward eating, and you may meet with a behavioral health specialist. You will have the chance to discuss your expectations and determine whether you are ready to make and stick to the lifestyle changes that are necessary for the surgery to work.

Keep in mind that a discussion of your attitude about food and weight loss is a two-way street. You won't necessarily be "told" that you are psychologically prepared for surgery or not. You will play a major role in determining your own readiness and need for bariatric surgery.

How to Prepare

A healthcare provider will describe the type of procedure you will have, the location and size of the scar you should expect, and the effects and side effects you should anticipate after your surgery. Ask any and all questions you have to feel comfortable before proceeding.

Preparation for bariatric surgery involves imaging tests like an abdominal ultrasound or computerized tomography (CT) that can help your surgeon plan out your procedure. If you have any structural abnormalities, such as an ulcer or a polyp, it might impact the approach that your surgeon will use.

You will need to have a complete blood count (CBC), liver function tests, and blood chemistry tests. While abnormalities in these tests probably won't contraindicate surgery, issues like anemia (low red blood cells) or low calcium would need to be corrected prior to your surgery. Additionally, you will need to have an electrocardiogram (EKG) for pre-surgical anesthesia testing.

You may also need to have some of your own blood collected and stored prior to your operation in case you end up needing a blood transfusion during surgery.


You will have your surgery in an operating room that's located either in a hospital or a surgical center.

What to Wear

You can wear anything comfortable to your surgery appointment. You will wear a surgical gown during your procedure.

Food and Drink

You will need to abstain from eating and drinking starting at midnight the night before your surgery.


The healthcare provider will give you specific instructions regarding medication. You might be given an adjusted prescription dose if you take steroids or medication for diabetes.

And you might be advised to stop or reduce the dose of any blood thinners you take for several days before your surgery.

Be sure the healthcare provider is aware of any and all medications and supplements you take.

What to Bring

You need to make sure that you have personal identification, health insurance information, and a form of payment for any portion of your surgery that you will be responsible for. You should also have a list of your medications and doses with you.

Your abdomen will be sensitive and might be sore after surgery, and you may have a surgical drain placed. Bring something to wear home that is loose and allows access to the drain.

You will need to have someone drive you home when you are discharged from the hospital after your surgery.

Pre-Op Lifestyle Changes

You might have a special diet in the months prior to your surgery. Generally, following a nutritional plan and achieving a target weight loss are recommended prior to bariatric surgery.

What to Expect on the Day of Surgery

When you go to your surgery appointment, you will need to register and sign a consent form. You will go to a pre-operative area where you might have some same-day tests, such as CBC, blood chemistry tests, and a urine test.

Your surgeon and anesthesiologist may come to see you before you go to the operating room.

Before the Surgery

You will have an intravenous (IV, in a vein) line started in your arm or hand; a urinary catheter will also be placed. Necessary equipment to monitor your temperature, blood pressure, pulse, respiratory rate, and blood oxygen level will also be set up.

A surgical drape will be put over your body, leaving the surgical area exposed. Your skin will then be cleaned with a surgical solution to reduce your risk of infection.

Your anesthesia will begin as the anesthetic medication is injected into your IV. This medication will prevent pain, paralyze your muscles, and put you to sleep. You will have a breathing tube placed into your throat to help you breathe during your surgery.

During the Surgery

Your surgeon will begin your procedure by making an incision in your skin. If you are having an open laparotomy, you will have a large incision that gives your surgeon access to your stomach and possibly your small intestine as well. The size and location of your incision for an open laparotomy depend on the exact procedure you are having.

If you are having a minimally invasive laparoscopic procedure, you will have four to six small abdominal incisions, which can be approximately 1 or 2 inches in length each.

After your skin is cut, you will have an incision into your mesothelium. This is a protective covering under your skin that encloses your abdominal organs. Your surgeon will then have access to your stomach and the surrounding area.

The next steps of your surgery can vary, depending on exactly which type of bariatric procedure you are having.

Your bariatric surgery will include one or more of the following steps:

  • Placement of a balloon in your stomach
  • Placement of a band around your stomach
  • Resection of part of your stomach and closing the stomach with sutures to prevent leaking of stomach contents
  • Cutting the opening of the intestine away from the stomach opening and surgically repositioning it to a new opening higher in the stomach

Throughout surgery, bleeding is controlled, and excess blood and fluid are suctioned. If necessary, a blood transfusion might be done during surgery to replace the loss of blood.

After the stomach and small intestine are optimally positioned and any incisions in those organs are closed, your surgeon will also close any incisions that were made in your mesothelium.

A temporary drain may be placed in your stomach, with the tube extending to the outside of your body for collection of inflammatory fluid. The drain may remain in place until the inflammation subsides, possibly several weeks after surgery.

Your skin incision will be closed and the surgical wound will be covered with surgical dressing.

Your anesthesia will be stopped and your breathing tube removed. Your anesthesia team will see that you are breathing independently before taking you to the surgical recovery area.

After the Surgery

In the recovery area, you will continue to have your blood pressure, pulse, respiratory rate, and oxygen saturation monitored. Additionally, your surgical wound may be checked. And if you have a drain, the fluid in the drain will be observed and emptied. You may receive pain medication.

You will have your urinary catheter removed and you will be able to use the toilet or a bedpan with assistance.

You will likely stay in the hospital for several days after your bariatric surgery. During your stay, you should gradually be able to get up and walk on your own and use the toilet independently.

While in the hospital, you will learn how to manage your drain if you have one.

During your hospital stay, you should be able to drink clear fluids; you might advance to thicker fluids or solids.

Advancing your diet will take place more quickly if you've had a band or ballon placed, and more gradually if you've had any part of your stomach or intestines cut. In the first few days after your surgery and as you are advancing your diet, you will also likely need to have IV fluid supplementation.

Your surgical team will also want to ensure that you are able to pass stool before you leave the hospital. Inability to do so after bariatric surgery is a sign of stomach or intestinal blockage.

Once you are ready to leave the hospital, you will receive instructions about at-home pain management, necessary follow-up, and more.


Because there are several different types of bariatric procedures, recovery can vary. Recovery time is longer if you have had part of your stomach or small intestine cut.

You will see a healthcare provider for a follow-up appointment within days after your discharge from the hospital, and again every few weeks for several months. During these visits, you will have your drain and stitches removed, your wound inspected, and your surgical dressing changed.


As you are healing in the first few weeks after surgery, you need to keep your surgical wound clean and dry. You should change your dressing and care for your drain as directed.

Signs of complications to look out for include:

  • Fever
  • Severe or worsening pain
  • Blood or pus seeping from the wound or found in the drain
  • Tenderness, redness, or swelling around the wound that's getting worse
  • Vomiting or hematemesis (vomiting blood)
  • Inability to pass stool
  • Severe diarrhea or blood in the stool

If you experience any of these signs, be sure to call your surgeon's office.

Coping With Recovery

As you are recovering, you may have some pain. You should take your pain medication and any other prescriptions you received as directed.

You might have restrictions on your physical activity for several weeks, but you should make an effort to move around within these limits to avoid issues that can occur due to inactivity, such as blood clots and pneumonia.


After any bariatric procedure, you can have abdominal pain and cramping, and you won't feel like you can tolerate food and liquids right away. You need to gradually increase your food and drink intake per a healthcare provider's instructions.

You will be given specific instructions about what you can eat and what you must avoid. For example, spicy foods can cause discomfort and fatty foods can cause diarrhea.

You can also feel full or bloated after eating and drinking small amounts. This is expected; in fact, this feeling is part of the purpose of your surgery. However, the discomfort may come as a surprise.

You will need to work with your medical team as you learn to adjust to your changed tolerance for food. Often, it is recommended to eat small amounts of food more frequently and to avoid foods that don't provide the nutrients you need.

Long-Term Care

You will need to follow up with a healthcare provider to ensure that you are healing well and that you are getting the nutrition you need.

You may need periodic blood tests to ensure that you aren't missing out on nutrients, and you might receive a prescription for a vitamin (e.g., vitamin D) or a mineral (like calcium or magnesium) if your tests show that you have a deficiency.

Some nutrients, such as vitamin B12, might not be well absorbed after bariatric surgery, so you may need IV supplementation.

Possible Future Surgeries

Generally, bariatric surgery is a single procedure that's not meant to be followed up with additional procedures.

A lap band can be adjusted (if needed) with a needle that is placed into the port, a process that does not involve another operation. Reversal of lap band surgery is not common, but you may need to have your band removed down the road if you develop complications, like an infection or a hernia.

And you may have your gastric balloon removed endoscopically at some point after you have achieved adequate weight loss.

If you develop adhesions due to your bariatric procedure, it could cause bowel obstruction years later, and the treatment can include surgery.

Lifestyle Adjustment

After having bariatric surgery, you'll have to commit yourself to a healthy diet and exercise to maintain your weight loss and avoid malnutrition. Chronic overeating can stretch the stomach and cause it to enlarge again, potentially canceling out the benefits of the surgery.

You will likely receive guidance from a nutritionist or a dietitian regarding the amount and type of food you should eat to stay well and maintain your results. And you may benefit from meeting with a behavioral health specialist who can help you adjust to your new weight and maintain a healthy attitude toward your lifestyle post-surgery.


Bariatric surgery is an option that can help achieve weight loss. It's usually tried when a person has developed risks or complications of excess weight and other weight-reduction methods such as lifestyle adjustments and medications haven't worked. There are several types of bariatric procedures, and a surgeon will choose the right one depending on a person's individual needs.

There are lasting health benefits of bariatric surgery, but there are also long-term lifestyle adjustments that you have to make to maintain the benefits.

10 Sources
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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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.