Bariatric surgery, or weight loss surgery, refers to any operation for weight loss that alters the digestive system in people with obesity. This surgery can be effective but comes with risks and requires permanent lifestyle changes to keep the weight off.
Bariatric surgery refers to a class of surgical procedures that support weight loss in people with severe, or class 3, obesity. Doctors mainly recommend bariatric surgery to those who have yet to see results from other weight loss methods.
Although the procedures carry risks for some people, a healthcare professional will determine whether complications are more likely to result from obesity than from the surgery.
What Is Bariatric Surgery?
Bariatric surgery aims to alter the intestines or stomach, often making the stomach smaller and bypassing part of the gut. This causes a person to eat less and feel less hunger, changes how the body absorbs food for energy, and increases satiety (feeling full after eating). The procedures aim to support people in maintaining a moderate body weight.
According to the most recent data, approximately 280,000 people in the United States underwent bariatric surgery in 2022.
On the day of surgery, patients can expect to receive general anesthesia. Depending on the type of bariatric surgery someone is having, the operation will take anywhere from one to two hours. Most operations are laparoscopic procedures, which means the surgeon inserts a small instrument with a camera through a tiny cut in the abdomen. This technique can speed up recovery time compared to surgeries requiring larger cuts.
Doctors currently perform three main types of bariatric surgery. A fourth type — the adjustable gastric band — is an older and more outdated procedure that surgeons no longer perform due to the effectiveness of more modern techniques.
Each surgery type has pros and cons to discuss with your doctor. “Each provides different average weight loss results and potential side effects or risks,” says Ellen Morrow, MD, an assistant professor and surgeon at the University of Utah Health who is certified in bariatric surgery.
“In general, it seems like the risk of a procedure sort of parallels the benefits,” she adds. “A sleeve gastrectomy, for example, may have a little bit less risk in some ways but results in a little bit less weight loss, while a duodenal switch may have potentially more long-term complications but also has the most significant weight loss results.”
Gastric Bypass
A Roux-en-Y gastric bypass is also known simply as a gastric bypass. "Roux-en-Y" is French for “in the form of a Y.” This procedure is a common choice in the United States.
“My colleagues and I here at the University of Utah perform Roux-en-Y gastric bypass the most, which is kind of considered the gold standard,” says Dr. Morrow. In this procedure, the surgeon separates the stomach into a top and bottom section.
The top section — also called a pouch — is roughly the size of an egg, and the bottom section no longer digests food. The surgeon then connects a part of the small intestine called the Roux limb to the new stomach pouch.
“The Roux-en-Y gastric bypass works through malabsorption, so for this procedure there is some intestinal rearrangement as well to alter your body’s hormonal response to food, which is important,” says Morrow.
Malabsorption occurs when the body is unable to absorb nutrients from food properly.“For a healthy person, malabsorption isn’t desirable, but in terms of bariatric surgery, it can be a benefit for weight loss,” adds Morrow, as it reduces calorie intake. However, because the body absorbs fewer vitamins and trace nutrients after surgery, following the diet that your doctor recommends is vital to prevent unwanted side effects.
The surgery typically takes 90 minutes.
After this surgery, average weight loss is about 70 percent of excess body weight.
Sleeve Gastrectomy
This option is the most popular kind of bariatric surgery. “Sleeve gastrectomy is currently the most commonly performed procedure nationwide,” says Morrow.
This procedure involves removing approximately 80 percent of the stomach. What remains is a stomach that’s about the size of a banana (and roughly the same shape).
“Bariatric procedures generally work in one of two ways, or sometimes both,” explains Morrow. “The first way is with restriction. All bariatric procedures have altered the stomach to try to make people have a smaller stomach and feel fuller,” she says.
“A sleeve gastrectomy works purely through restriction, so we’re creating a smaller stomach by removing about two-thirds of the stomach.” A sleeve gastrectomy is the simplest of the procedures and doesn’t require as much time on the operating table. “It takes approximately an hour to perform,” says Morrow.
People may lose 30 to 80 percent of their excess weight after a sleeve gastrectomy.
Duodenal Switch
Biliopancreatic diversion with a duodenal switch is often called a duodenal switch. “A duodenal switch involves a bit more malabsorption [compared with the gastric bypass],” says Morrow.
This surgery has two key steps. The first is to perform a sleeve gastrectomy, leaving about 20 percent of the stomach.
The second step is to connect the end of the intestine to the duodenum, a tiny portion of the small intestine that connects to the stomach. This bypasses far more of the intestine than a gastric bypass. The result is that you’re unable to eat as much or absorb as many nutrients, including fats and proteins.
This surgery can lead to more significant weight loss than others, with people losing around 80 percent of excess weight after a duodenal switch. It’s especially effective for patients with type 2 diabetes. But it comes with more significant risks than other options.
Duodenal switches take longer than other options, typically lasting between 90 minutes and three hours.
While a specific diet is crucial for everyone who undergoes bariatric surgery, following eating guidelines closely is necessary for people who have a duodenal switch.
“They have to be really careful about eating enough protein, or else they can become deficient, and drinking enough water so they don’t get dehydrated. Plus, they must take vitamins daily, often more than once a day, depending on which vitamin supplements they choose,” says Morrow.
People undergo bariatric surgery primarily to lose weight and improve obesity-related diseases if they have obesity. Doctors will consider bariatric surgery if other weight loss methods haven’t worked and the person’s overall health is at risk.
Body mass index (BMI) is one selection criteria that helps doctors determine whether you’re a candidate for bariatric surgery. This figure doesn’t give the whole picture of health, but you can work it out by multiplying your weight in pounds (lb) by 703, dividing the result by your height in inches, and then dividing that result again by your height in inches. The final answer is your BMI.
According to the American Society for Metabolic and Bariatric Surgery, doctors should consider bariatric surgery for the following individuals:
People with a BMI of 35 or higher
Adults who have a BMI between 30 and 34.9 and a metabolic disease, such as diabetes
“Appropriately selected” children and adolescents
Doctors should also consider Asian people for bariatric surgery if their BMI is above 27.5.
When deciding whether or not someone should have bariatric surgery, doctors will also take into account various risk factors to ensure that it’s a safe option. “We don’t want to do surgery if it’s not going to be safe for the patient,” says Morrow.
These risk factors include:
Smoking
Substance use
How well the patient is managing any mental health conditions they have
Doctors will medically screen you for tobacco, drugs, and excessive alcohol consumption. If levels are high, they may ask that you quit before they attempt surgery.
Follow-up visits will be necessary to track recovery and progress, usually at 10 to 14 days, six weeks, three months, and six months after discharge. These then switch to yearly check-ins to support weight loss and prevent a person from putting the lost weight back on or developing nutrient deficiencies and late complications.
If you lose weight and remain healthy, consider discussing body contouring surgery with your doctor. Rapid weight loss can lead to loose skin and tissues, which body contouring can tighten.
A lot of changes occur after bariatric surgery, and while scheduled appointments with a mental health professional are not part of the standard aftercare, they could be helpful for some. Research suggests that 1 in 6 people use a mental health service afterward. Be sure to raise any postsurgical mental health concerns with your doctor.
Risks and side effects can be minor or something you’ll need to see your doctor for. Here are some of the potential side effects and complications of bariatric surgery.
Risks
While very uncommon, certain complications do arise after bariatric surgery.
Causes of concern in a recovering patient include an abnormal heart rate, fever, and an unusual amount of pain, says Morrow. “The rate of more serious complications — blood clots and leaks — is around 1 percent.”
Several mild side effects can occur after bariatric surgery, while rarer side effects can have a bigger impact on a patient’s quality of life and health.
Potential side effects that can occur with bariatric surgery include:
Some people may need to have a second surgery or procedure.
Leading up to surgery, living with obesity can lead to feelings of shame, low self-esteem, depression, or anxiety. The surgery itself can present fear and uncertainty. After this, bariatric surgery leads to a significant life change involving a new lifestyle, changing relationships, and body image issues.
Proper care after bariatric surgery is essential because it alters your gastrointestinal system. You’ll need to follow a special diet for life and be monitored by medical professionals yearly. People will need to make the following changes after the surgery, some of which are lifelong:
Taking steps to quit smoking permanently because nicotine can increase the risk of heart attacks, pneumonia, blood clots, and slow recovery
Reducing or stopping alcohol because the body absorbs alcohol faster after bariatric surgery
Avoiding pregnancy within 12 to 18 months of the procedure, which can help an individual control body weight and get enough nutrition for a healthy pregnancy
Other considerations include diet and nutrition, exercise, and mental health care.
Medications
People should speak to their healthcare provider about which medications they may need. However, they may be able to decrease or stop taking medicines from before the surgery per a doctor’s instructions. They might also need to change the form of extended-release medications, for example, moving from pills to liquids.
Once the surgery is complete, you’ll wake up in a recovery room. The staff will monitor you for complications, and you’ll likely need to stay in the hospital for one night after most bariatric procedures — or for a few nights after more complex procedures like a gastric bypass.
You may be walking on the day of the surgery and sipping fluids while you’re still in the hospital. “We encourage all our patients to get out of bed and walk within two hours of the surgery,” says Kristen Smith, RD, a spokesperson for the Academy of Nutrition and Dietetics and a bariatric program manager at Piedmont Healthcare in Atlanta.
However, people should avoid lifting loads heavier than 10 pounds for four to six weeks after the procedure.
Nutrition and Diet Progression
To prevent malnutrition or weight gain after bariatric surgery, you’ll need to follow a healthy eating plan and meet regularly with a registered dietitian.
“Patients should meet with a dietitian regularly for at least the first year, and then we ask our patients to return annually after that,” says Morrow.
In the first month, the postsurgery diet requires a specific strategy. “I often refer to it as similar to feeding a baby,” says Smith. The diet progression starts with liquids, moves on to pureed food, and eventually reaches solid meals. Returning to a normal diet might take up to 12 weeks.
The diet may vary depending on the doctor or dietitian, says Morrow, but some of the main recommendations include:
Avoid soda.
Eat 60 to 100 grams of protein a day.
Drink at least 64 ounces of water a day.
Eat frequent small meals.
Emphasize protein-rich foods.
Minimize refined carbohydrates.
Avoid food and drinks with refined sugars.
The nutritional profile and quality of the foods you consume are also key. “We definitely emphasize lean protein, vegetables, and dietary fiber,” says Morrow. In addition to helping you stick to a specific eating plan, a nutritionist may offer straightforward strategies for following the diet, such as meal planning.
Take Supplements
After bariatric surgery you need to take supplements for life to prevent serious diseases that can come with vitamin and mineral deficiencies.
You might feel a new burst of energy after bariatric surgery, and exercise can help you keep off the excess weight.
However, check with a surgeon about when you can start exercising at full intensity after surgery. You may be able to start walking within a few hours of surgery, which can support a quicker recovery. Once your surgeon confirms that it’s safe to exercise, aim for 30 minutes of moderate exercise daily.
Seek Mental Health Help if Needed
Given the challenges that come after bariatric surgery, you might benefit from having a support system that can help you process the complex self-image changes around rapid weight loss. Consider being open with family and friends, joining a support group for people on the bariatric surgery journey, or seeking consultation with a psychological health professional. Bariatric surgery teams may provide counseling services.
Bariatric surgery is an effective way to lose weight for people with obesity when other treatment options have not worked.
Each type of weight loss surgery comes with potential benefits, risks, and side effects and requires a long-term commitment to making diet and other changes.
Patients must understand the lifelong commitment to a healthier lifestyle necessary to make bariatric surgery successful.
