My Doc requires a pre-opm diet - to lose 5% of your body weight before surgery. It is a lo carb high protein diet. The reason is two fold....one that type of diet makes the liver shrink because it sits on top of the stomach -So the surgery is easier on you AND he wants to see that you can follow a diet - because to be successful after surgery - YOU MUST follow their instructions so you don't have problems and you don't gain weight. Carlotta