If you are T2 diabetic, then the only successful surgery procedure for controlling sugar levels appears to be the Roux-Y bypass, which is not banding. The Newcastle Diet plan was tested as a means of emulating the bariatric surgery but without the surgery, and it has similar success rate to the surgery. It is also repeatable. the ND diet is capable of causing weight loss of around 15kg. Obviously there are other reasons for having surgery so maybe something to discuss with your consultant.