You need to clear out your stomach and shrink it before surgery so yes, it does matter, and theres that whole fatty liver thing, which we all have, or we wouldnt be having the sleeve. Surgery is very very stressful to your body, you want to be as healthy as you can be before going in. I wonder if you should think about your commitment, because if you can't follow pre-op, how successful can you be post-op? I'm not sure why doctors require clear liquids the week before, mine didn't, I just did 2 weeks of protein shakes and vegetables, then 2 weeks of protein shakes and clear liquids. This is one month of your life, and the practice you need to control impulses. You can have a little fast food after you heal, no need to keep giving it a farewell party