Can Bariatric Surgery Cure Type 2 Diabetes?

Weight loss surgery has long been touted as an effective treatment for severely overweight people, but did you all know it can reverse type 2 diabetes?

doctors in surgeryNot every person with type 2 diabetes is a candidate for bariatric surgery but research shows it does a better job at managing diabetes than insulin or oral medications. (Photo: Unsplash, Marlon Lara)

Following weight loss surgery, more than 70% of type 2 diabetes patients were in remission, according to a recent review of multiple studies.1 Even five years or more after surgery, 84% of patients were still in remission, or their diabetes remained significantly improved. 2

In fact, surgery does a better job at managing diabetes than insulin or oral medications. 3,4  For instance, a 2014 review found that more than 63% of weight loss surgery patients were in remission from diabetes, compared to less than 16% of medical management patients.5

What Is Bariatric Surgery?

Bariatric surgery refers to several procedures, including adjustable gastric band surgery, gastric sleeve surgery (or sleeve gastrectomy), gastric bypass (also known as Roux-en-Y gastric bypass) surgery), and biliopancreatic diversion with duodenal switch.

Weight loss surgeries shrink the stomach, either by removing most of it (sleeve gastrectomy, duodenal switch) or by creating a small pouch for food (adjustable gastric band, gastric bypass). A smaller stomach means you’ll feel fuller with less food.

In addition, with gastric bypass and duodenal switch surgeries, “We reroute the path that food takes through your body,” according to Scott A. Cunneen, MD, FACS, FASMBS, director of metabolic and bariatric surgery at Cedars-Sinai Medical Center, Los Angeles, and author of 21 Things You Need to Know about Diabetes & Weight Loss Surgery, published by the American Diabetes Association.6 In these procedures, as well as with sleeve gastrectomy, food moves more quickly through the gastrointestinal system, and fewer calories are ingested.

These surgeries also prompt changes in gut hormones that affect metabolism and appetite.7 As Dr. Cunneen explains, “The delivery of food into the intestine at a different rate than usual makes communication changes that make people feel less hungry, and in the case of people with diabetes, handle sugar better.”

Types of Bariatric Surgery

Adjustable gastric band surgery: During this procedure, a surgeon inserts a band around the top of your stomach, creating a small pouch. The band is attached to a port placed under the skin, and is adjusted regularly, at least at first, to make sure the size of the opening between the pouch and the rest of the stomach maximizes weight loss while minimizing unpleasant side effects. The surgery is usually performed laparoscopically—a minimally invasive procedure that involves just a few small incisions in the abdomen. These days, gastric band surgery is rarely performed.9 The band can be removed.

Gastric sleeve surgery (vertical sleeve gastrectomy): Most of the stomach is removed during this procedure. It is often performed laparoscopically and made up almost 60% of all weight loss surgeries in 2017.8 It is irreversible.

Gastric bypass surgery (Roux-en-Y gastric bypass): This is a two-part procedure. First, the surgeon staples your stomach, forming a small upper section. The surgeon then connects this section to the lower part of the small intestine, creating a shortcut that avoids most of the stomach and part of the small intestine. In 2017, nearly 18% of all weight loss surgeries were gastric bypasses.8

Duodenal switch surgery (biliopancreatic diversion with duodenal switch): As with gastric sleeve surgery, most of the stomach is removed. What remains is connected to a tube that bypasses most of the small intestine. This complex surgery is usually reserved for very obese patients, and generally results in the biggest weight loss. It is rarely performed.8

Who Is a Candidate?

Weight loss surgery is often recommended for diabetes patients with a body mass index (BMI) of 35 or more, and anyone with a BMI of 40 or more.9 It may also be an option for some people with BMIs of 30+,10 which is considered obese.

Surgery is not appropriate for every diabetes patient, but one UK study found that 52% of people with type 2 diabetes were obese,11 so it’s likely an option for a significant number of patients. Dr. Cunneen estimates that about one-quarter of his weight loss surgery patients have type two diabetes.


While weight loss surgery is not without risks for type 2 diabetes patients, especially those who smoke or have chronic obstructive pulmonary disease,12 only 1-4% of patients develop major problems.12 For all weight loss surgery patients, the risk of dying during or after surgery is very small—less than 1 in 1,400.13 It is also safe and effective for people over 60.14

All in all, weight loss surgery lowers death rates linked with type two diabetes and is associated with better odds of long-term survival among obese people.15,16,17

After Surgery

You may see improvements in your blood sugar levels quickly—within two weeks among gastric bypass and duodenal switch surgery patients.18

Since most weight loss surgeries interfere with your ability to absorb nutrients, taking daily multivitamin (vitamins B and D are particularly important) and mineral (especially calcium) supplements are important.19

To maximize and maintain both weight loss and good blood sugar control after surgery, a healthy diet and regular exercise are key. Fortunately, eating right shouldn’t be too difficult, since after surgery, “The hunger is really controlled, so you’re not starving when you’re trying to reduce the calories,” Dr. Cunneen explains.

Weight loss is comparatively slow for gastric band patients, but gastric bypass and sleeve gastrectomy patients lose “a lot—two-thirds or so [of the total weight lost] within the first six months,” Dr. Cunneen notes. He estimates that that if you have 100 pounds to lose, you’ll lose about 70 pounds within 18 months.

Dumping Syndrome

Between 20 and 50% of weight loss surgery patients experience dumping syndrome, which is characterized by symptoms such as nausea, vomiting, diarrhea, fainting, dizziness, and even shock after meals.

Patients with dumping syndrome should eat more frequently, delay their liquid intake until at least a half hour after meals, and avoid certain foods, including milk products and sugary foods. Medication and surgery can also treat the condition.20

Long-Term Outcomes

Unfortunately, weight loss surgery isn’t always a permanent solution for people with type 2 diabetes. A significant percentage of people who are in remission a year after surgery later relapse. Long-term remission is more common in patients with a recent diabetes diagnosis, no history of insulin use, and better diabetes control prior to surgery. However, even if your diabetes returns, symptoms are often less severe, and can usually be controlled with fewer medications.21

In addition, patients often gain back some of the weight lost. Dr. Cunneen says that if you lose 70 pounds after surgery, “After five years, you’ll have 50, 55 out of those 70 pounds you lost still off.” While weight loss surgery is not an easy—or a guaranteed—solution for people with type 2 diabetes, it could be just what you need. As Dr. Cunneen says, “With these surgeries, if you try to eat healthy, the body rewards you by making you satisfied with what you’re eating.”

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Episode 27: Is Bariatric Surgery Right for You?