The reversal is nearly instantaneous, even before a patient loses weight.
For the first time, the International Diabetes Federation is recommending surgery as a treatment for diabetes in obese patients.
Gastric bypass surgery reduces the size of the stomach, so a person eats less. It also shortens the intestine, so fewer calories are absorbed.
However, it is unclear how the procedure normalizes blood sugar.
"The fast effectiveness, is due to, we think, an elaboration of hormones made by the intestines. These are called incretins," said Cleveland Clinic's Dr. Phil Schauer.
Doctors at the Bariatric Metabolic Institute of the Cleveland Clinic say some patients can come off insulin within hours of undergoing the surgery.
Keep in mind, although surgery may be recommended, that does not guarantee it's covered by insurance.