Doctors often counsel patients with type 2 diabetes to lose weight. It's a proven way to manage the disease and reduce the risk of serious complications. But how you lose weight can make a difference.

Most people lose weight by eating less or exercising more. But in severe cases, doctors sometimes recommend weight loss surgery. In the most common procedure, the surgeon removes part of the stomach and small intestine.

Gastric bypass surgery, as it's called, is highly effective, but weight loss isn't the only benefit.

Doctors who treat diabetes have known that patients who get the surgery often get their blood sugar under control quickly - even before they lose weight.

Now, researchers think they are starting to understand why.

"What we've shown is that after gastric bypass surgery - that has been shown before actually - the levels of circulating amino acids decreased significantly." says researcher Blandine LaFerrère. "But what's novel here [is] that we did not see that in the diet group, although they lost the same amount of weight."

Blandine LaFerrère works at the New York Obesity Nutrition Research Center, at a hospital affiliated with Columbia University.

The increase in these particular amino acids in patients that had the surgery signals that their metabolism has changed. But the details are still unclear.

"I think the hope of the research in gastric bypass surgery," she says, "is to develop new treatments, and those treatments would be based on a better understanding of what causes type 2 diabetes."

LaFerrère says many other researchers around the world are also working on the same problem.

"And I think when we're able to integrate all the clues and all the facts of the changes that occur after gastric bypass, we might be able to find some new clues and new help in the treatment of type 2 diabetes."

If researchers can understand exactly how weight loss surgery leads to better blood sugar control, even before the patient loses weight, they may be able to turn that knowledge into a medicine or other treatment that could help people with diabetes.

Blandine LaFerrère's research paper is published in the journal "Science Translational Medicine."

gastric bypass: 胃绕路手术（减小胃的容积, 达到减肥作用）

amino: 氨基的

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（来源：VOA 编辑：崔旭燕）