COVID Updates: Due to the increased spread of COVID, visitor restrictions have changed and medical-grade masks are now required in all Scripps facilities. See FAQs for details.

Can Bariatric Surgery Treat Type 2 Diabetes?

Weight-loss procedure can treat obesity and type 2 diabetes

A patient with obesity and type 2 diabetes discusses bariatric surgery with her doctor.

Weight-loss procedure can treat obesity and type 2 diabetes

If you are severely overweight and have type 2 diabetes, bariatric surgery may be an option to treat both conditions.


You’re not alone with these conditions either. Most people with type 2 diabetes are overweight or have obesity, according to experts.


Bariatric surgery is generally an option for people with obesity who are unable to lose weight through diet, exercise, lifestyle changes and medications.


The weight-loss surgery has also shown to be an effective treatment for type 2 diabetes.


“Weight-loss surgery is an effective intervention for people with obesity and type 2 diabetes especially when other therapies for morbid obesity fail,” says William Fuller, MD, a bariatric surgeon at Scripps Clinic. “It’s considered when the patient has done everything to lose weight, but cannot achieve significant, sustained weight loss.”

What is type 2 diabetes?

Type 2 diabetes affects the way the body process blood sugar or glucose. The condition requires treatment to prevent long-term health problems, including heart disease, stroke, blindness, kidney failure and amputations.


Studies have shown bariatric surgery leads to improvement or remission of type 2 diabetes in most patients. It treats diabetes by controlling how much sugar is in the blood.

How does bariatric surgery work?

The surgery causes weight loss by reducing the size of the stomach, which limits the amount of food it can hold. It also causes hormonal changes that help reduce hunger and increase the feeling of fullness.


Blood glucose levels can also change. “Blood glucose levels start to improve after surgery, even before large amounts of weight loss,” Dr. Fuller says. “As a result, many patients are able to scale back on medications for diabetes and go into remission.”


Dr. Fuller speaks from experience. He has performed more than 2,000 weight-loss surgeries. Up to 40 percent of his patients have diabetes, he says.

Who’s a candidate for bariatric surgery?

Bariatric surgery may be an option for adults who have:


  • A BMI of 40 or more 
  • A BMI between 35 and 39.9 and a serious health problem related to obesity, such as type 2 diabetes, heart disease or severe sleep apnea


Obesity also increases the risk of severe illness from COVID-19. Losing weight can help reduce many of these risks.

Types of surgery

The most common weight-loss procedures are gastric bypass and gastric sleeve. Both are considered safe and effective for treating type 2 diabetes.

Gastric bypass surgery

In gastric bypass, the surgeon reduces the size of the stomach by creating a small pouch on top of the stomach. The effect is that you feel full after eating just a small amount of food. Studies show the surgical procedure causes remission of type 2 diabetes in 80 percent of patients.


“This procedure appears to set in motion certain chemical changes in the patient’s body that help set up better control of blood sugar levels,” Dr. Fuller says. “Gut hormones involved in appetite and weight reduction are altered.”

Gastric sleeve

In this procedure, also called sleeve gastrectomy, the surgeon removes 80 percent of the stomach. The remaining portion is formed into a tube-like sleeve. The smaller stomach can hold only about two ounces at any given time. An average stomach can hold up to two quarts.


The procedure also removes parts of the stomach that produce hormones associated with hunger. It causes weight loss by limiting the amount of food one can and decreasing appetite.


Diabetes remission rates after the procedure are high at more than 60 percent, according to studies.

Is bariatric surgery safe?

Bariatric surgery is considered a safe procedure but with any surgery there are still risks. “Your surgeon will discuss with you all risks and expectations,” Dr. Fuller says.


“This type of surgery is considered only when other efforts have failed, and the patient is at risk for other serious conditions. The risks posed by the surgery are greatly outweighed by the risks of being obese,” he says.


Minimally invasive surgical techniques are typically used in weight-loss surgery. Small incisions are used to operate, which helps with recovery. The procedure results in less pain, less time in the hospital, fewer complications and better cosmetic results.


“Perhaps the biggest concern is adjusting medication requirements after the procedure to account for the body’s changing needs,” Dr. Fuller adds.

Life after surgery

While the procedure can lead to significant weight loss, it is up to the patient to maintain their new weight through long-term lifestyle habits. This is important to achieve long-term success.


Lifestyle changes include eating more whole foods, avoiding processed foods and increasing physical activity.

The importance of patient choice

Athena Philis-Tsimikas, MD, an endocrinologist and corporate vice president of the Scripps Whittier Diabetes Institute, says any method that significantly reduces caloric intake can yield positive results. She stresses the importance of non-surgical options before surgery is considered.


“It’s important that patients understand how limiting calories is essential to diabetes care, and that there is a full spectrum of options to achieve this,” she says.