That study finds gastric bypass is significantly better.
Obese diabetics who had gastric bypass lost 64 percent of their excess weight after a year, compared with 36 percent in those treated with lap-band.
Complication rates were about the same with both procedures.
In gastric bypass doctors surgically reduce the size of the stomach to limit the amount a person can eat.
Gastric banding involves inserting an adjustable silicone band around the upper part of the stomach, giving the patients the illusion of fullness with small meals.
The study appears in the Archives of Surgery.