I have my surgery next week and am worried about the same thing. I have been seeing a Phycologist for a couple of months to prepare me. Maybe try talking to a Heath professional about it and ways to deal with it. It's my big concern so I definately get ya!
I am booked sept 19! Terrified and beyond excited all at once!!! Is it weird to be scared not to be able to rely on food!? It's been my security for sooo long!!