CHICAGO (AP) -- New research provides clear proof that weight-loss surgery can reverse and possibly cure diabetes. Doctors say it should be offered sooner to more people with the disease -- not just as a last resort.

Two studies compared stomach-reducing operations with medicines alone for obese people with Type 2 diabetes. Millions of Americans have this and can't make enough insulin or effectively use what they do make.

The studies found that surgery helped far more patients achieve normal blood-sugar levels than drugs alone did. Some people were able to stop taking insulin as soon as three days after their operations.

The studies were published online by the New England Journal of Medicine and one was presented Monday at a cardiology conference in Chicago.