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How Bariatric Surgery Improves Diabetes

Many diabetics can stop taking medication after surgery

The most dramatic benefit of weight loss surgery isn't just a drop in pounds: Type 2 diabetes also improves significantly in most people or even goes into remission.

This change is made possible, in part, by hormones that go up — and down — after surgery.

During two of the most common types of bariatric surgery, either the digestive tract is re­arranged or part of the stomach is removed — altering the levels of hormones released by the gut, says Alfonso Torquati, MD, a bariatric surgeon at Rush University Medical Center.


Produced in the intestines, this hormone normally spikes after a meal. Its job is to help insulin move glucose (sugar) out of the bloodstream and into cells.

But in people who are obese, GLP-1 doesn't spike as it should after eating.

Research by Torquati and colleagues found that GLP-1 goes up substantially following a meal very soon after patients have bariatric surgery. And more GLP-1 means more help for insulin with regulating glucose.

"That's why a lot of people can come off diabetes medication right away after surgery — even before they lose weight," he says.

Appetite hormones

The hormone peptide YY, which helps the body feel full after a meal, also increases; meanwhile, the hormone ghrelin, which signals the body to eat, decreases after bariatric surgery.

These hormonal changes help people lose weight without feeling famished. And eating fewer calories and carbohydrates plays a key role in controlling diabetes, Torquati says.

"At Rush, one of the things we want to study next is how these gut hormones respond differently in different races," Torquati says.

A lot of people can come off diabetes medication right away after surgery — even before they lose weight.

Fast fact

The American Diabetes Association recommends bariatric surgery as a first-line treatment for people with a body mass index (BMI) over 35. Calculate your BMI.

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