I had to do one and it SUCKED. See my blog for ref, but I totally feel your pain. You've got to try your best, and if you're gonna cheat, don't cheat with carbs, cheat with protein. I had soft-boiled eggs sometimes. The reason is if you limit your carbs then you'll go into ketosis, and once you're in ketosis, which takes 3 or 4 days of lowww carbs you stop really feeling hunger, which makes the diet WAY easier.