Depending on how much weight I cut I will adjust my eating the night before a contest.... when you compete, you want to weigh about what you would in training. I've had meets where I bloat back to where I normally am and done great.... and I've had meets ( like nationals this year) where I bloated to 10lbs OVER what I walk around at.... that was a bad day.
That morning, I stick to my routine. The same brand and flavor of protein that I always have. One of three or four different foods that I know won't mess my world up. The big thing is to not eat or do anything that you wouldn't do before a heavy training day.
The day of the meet I always pack a ton of food and drinks. You never know what will be available at the meet site, or how long the meet will go. So, 3 or 4 PB+J sandwiches, some veggies, V8, a dozen gatorades and water bottles, bananas, yogurt, protein shakes....