I am having class 9 this friday, graduating Sept 14th. Our class brought up the 10% weight loss because it was acted by the instructors that it was "mandatory" and the lady we had that week ( I think it was a dietitian or psych) told us its PREFERRED. It makes surgery easier and shows your commitment, but they can't FORCE you to loose weight. They said that it makes you more likely for the surgeon to say go ahead with the surgery faster. I have a co worker who did options, then has his surgery this past Feb, he GAINED weight through the program, he did the "eat everything before I can't eat it anymore". His surgeon actually told him, you know what, I can not supposed to do it, but I will anyways. Def. not saying to go his way cus who knows. But our class was freaking out over the "required" 10% weight loss. By that I am supposed to loose 31 lbs, I have changed habits of eating and what not, and have lost 15, so its still going to show them the commitment.