My surgery is May 20th too. I started my preop diet May 6th which consist of 4 mandatory meal replacements a day (bought from doctors office) and all the non starchy green veggies I want, and 1 4oz piece of lean meat a day. No milk, cheese, pasta, rice, crackers, bread... So it's basically a high protein, no sugar diet. I have lost 7.4lbs so far! Whoohoo! I'm beginning to get a little nervous. But I know this is what I need! I'm 5'2 and my highest weight was 254.4 and I'm now at 247 lbs.