I porked out for a few weeks prior to the pre-op diet with all my food funerals (plus it was Christmas) so I gained 13 lb. I lost the 13 lb in the 2 weeks of the pre-op diet. I liked that Aceves had no restriction on amounts of food- just the type. The idea is just to get your liver in shape for the surgery. It needs to be "less juicy" and the way to do that is to get it into a state of ketosis. If it is "less juicy" then when it is manipulated during the surgery (to get it out of the way of your stomach)there is less chance that it will bleed.It is more practical than you might think to follow the high protein diet prescribed...It is not just to lose weight.