Bariatric surgery, or weight loss surgery, is an effective tool for long-term weight loss in people with type 2 diabetes and obesity.

Roughly 13% of adults in the United States have diabetes, according to a 2020 report from the Centers for Disease Control and Prevention (CDC). Nearly half of people with diabetes also have obesity, which means that they have a body mass index (BMI) over 30.

In fact, there is a strong link between obesity and the risk of developing type 2 diabetes. If a person has diabetes, their doctor may recommend losing weight as part of the treatment plan.

Bariatric surgery is a weight loss procedure that healthcare professionals recommend for some individuals with obesity. They are also increasingly recommending it to treat type 2 diabetes in some people with obesity.

Bariatric surgery can improve type 2 diabetes by lowering blood sugar and reducing the need for medications. It may even result in long-term or permanent remission from diabetes.

However, bariatric surgery is considered a major surgery, and it does carry some short- and long-term risks and side effects.

Bariatric surgery refers to a group of surgical procedures that help a person lose weight by changing their digestive system.

These procedures typically make the stomach much smaller, which helps a person feel full sooner and eat less food overall. They also usually limit the ability of the small intestine to absorb calories from food.

Bariatric surgery can also affect certain hormones to reduce a person’s appetite and improve how their body metabolizes fat and uses insulin.

Because the bodies of people with type 2 diabetes become resistant to insulin, bariatric surgery may be helpful for treating diabetes.

Some research suggests that bariatric surgery can help people with type 2 diabetes better control their blood sugar levels in addition to improving weight loss, cholesterol levels, blood pressure, and kidney function.

Healthcare professionals are increasingly recommending it for people with obesity and comorbid conditions such as heart disease and diabetes.

Several types of bariatric surgery can decrease the amount of food a person can eat at one time. Some procedures also reduce the absorption of nutrients.

The following sections will look at the different types of bariatric surgery in more detail.

Gastric bypass (Roux-en-Y)

For this permanent procedure, a surgeon staples off the top part of the stomach from the rest of the organ. The resulting pouch will only be able to hold about an ounce of food.

The surgeon then cuts a lower part of the small intestine and attaches the pouch to it. This reduces the amount of time that food spends in the small intestine. The less time that food spends there, the less the body absorbs it.

Vertical sleeve gastrectomy

This surgery is sometimes also called stomach stapling. It works by permanently removing about 80% of the stomach to leave just a long pouch. It is not necessary for the surgeon to reroute the intestine for this procedure.

Laparoscopic adjustable gastric banding

In this procedure, a surgeon makes small incisions in the abdomen. They insert a tube with a camera called a laparoscope through the incisions and insert a band on the upper part of the stomach.

Other types

Some other, less frequently used types of bariatric surgery include the duodenal switch and the Maestro system, which uses an implantable device that reduces appetite.

As with any surgery, bariatric surgery poses some risks. These include:

  • dumping syndrome, which refers to when food enters the small intestine rapidly, resulting in abdominal pain, sweating, nausea, and vomiting
  • leaks in the gastrointestinal tract
  • inflammation of the lining of the abdomen
  • infections
  • reactions to the anesthetic the surgeon used during the procedure

After surgery, the body will not be able to absorb as many nutrients. For this reason, a person should take vitamin and mineral supplements as their doctor recommends.

This helps reduce the risk of significant nutritional deficiencies — such as chronic anemia, vitamin B12 deficiency, and vitamin D deficiency — which can lead to other complications over time.

Death is another rare potential risk. The American Society for Metabolic and Bariatric Surgery estimate that the risk of death is 0.16% within 30 days of surgery.

Side effects

Side effects directly following bariatric surgery may include:

  • bleeding from the site where the surgeon sewed the sections of the stomach together
  • diarrhea
  • blood clots

Later on, side effects may include:

  • an inability to absorb enough nutrients, which can lead to anemia and osteoporosis
  • gallstones
  • narrowing of the new stomach or the connection between the stomach and the small intestine (strictures)
  • hernias

Before considering bariatric surgery, healthcare professionals typically ask people to try other weight loss methods, such as making dietary changes, exercising, and trying certain medications.

Healthcare professionals should also evaluate a person’s individual risks before recommending surgery for them.

In general, they may recommend surgery for people with diabetes who have:

  • a BMI over 40, even if their diabetes is well controlled through the use of medications
  • a BMI between 35 and 39.9 and diabetes that is not well controlled with medications
  • a BMI between 30 and 34.9, diabetes that is not controlled with medications, and other major weight-related health conditions

A person may not be a candidate for bariatric surgery if they have:

  • an inflammatory condition of the gastrointestinal tract, such as Crohn’s disease
  • a history of previous bowel surgery or trauma
  • a serious heart or lung disease
  • portal hypertension
  • recently recovered from a heart attack or stroke
  • undergone long-term steroid treatment
  • an allergy to any of the materials used during surgery
  • serious illnesses, such as cancer, pancreatitis, or liver disease
  • an untreated or unstable mental health condition or substance use disorder

Most large insurance companies, as well as Medicare and Medicaid, cover bariatric surgery for people who meet certain criteria. A person should reach out to their insurer directly to learn more about these requirements.

For example, some insurance companies may require a person to have a BMI over 40 with proof from a healthcare professional that previous medically supervised weight loss programs did not help.

Other insurers may cover the surgery if a person has a BMI between 30 and 39.9 and at least one significant comorbidity, such as heart disease, diabetes, or sleep apnea.

In most cases, a person will need to pay for a portion of their care out of pocket, even if they have health insurance. The cost of surgery could still be several thousand dollars, but it may be as low as $0 depending on the plan, its deductible, and its out-of-pocket maximum. It is a good idea to contact one’s insurer first to understand these details.

Without insurance, bariatric surgery can cost between $7,000 and $34,000.

The long-term benefits of bariatric surgery may include:

  • improvements in type 2 diabetes, high blood pressure, heart disease, high cholesterol, kidney disease, and sleep apnea
  • improvements in knee, hip, and other body pain
  • improved mental health
  • prolonged life
  • a reduced need for prescription medications, including insulin
  • lower medical costs

Regular follow-up visits are necessary in the long term. Healthcare professionals will monitor a person’s weight and look for signs of potential complications, such as vitamin deficiencies.

Long-term studies suggest that the weight loss and other benefits associated with bariatric surgery last for many years. Some research also suggests that people with diabetes who have undergone bariatric surgery are often able to stop taking insulin altogether.

The greatest benefits seem to be in people who continue to adhere to a healthy, low calorie diet, get regular physical activity, and attend regular follow-up appointments with their doctor.

For some people, bariatric surgery may not produce the expected results. A person should contact their doctor right away if they are not losing weight or if they develop complications following the procedure.

Bariatric surgery is an effective tool against obesity and type 2 diabetes. It may be an option for people with obesity and diabetes who have been unable to lose weight with other lifestyle modifications or medications.

Although the benefits of bariatric surgery are evident, surgery is just one tool for treating obesity and type 2 diabetes. A healthy diet and regular exercise are still necessary for long-term success.

Before choosing bariatric surgery to treat type 2 diabetes, a person must commit to lifelong maintenance of diet, exercise, and regular healthcare visits.