Surgery for people who are extremely overweight is nothing new, but a good side effect is starting to raise some eyebrows in the medical community.

A study published in the New England Journal of Medicine indicates patients who undergo bariatric surgery for weight loss are seeing almost immediate reversal of their diabetes.

The blood sugar changes are happening even before the weight loss begins, says Carlos Galvani, associate professor of surgery at the University of Arizona College of Medicine.

Doctors believe the changes are caused by an altering in the way hormones act following the surgery. Despite the positive effects, there are still questions about the results of the test within the medical community, Galvani says.

The study took place at the Cleveland Clinic and a hospital in Rome.