Dont worry so much about what you eat the day before and focus more on what you will be eating during the tournament. I never even consider what I'm eating the day before, but I wouldn't recommend eating fast food or anything.
You want high energy foods with carbs. Its important to not feel hungry and keep a high level of energy.
Salty food with lots of water will prevent cramping.
Starches will keep you from feeling hungry without stuffing your face with 1/2 a pizza pie
High energy food like trail mix will keep you going
I usually bring a small ham sandwich as well.
So, my tournament food includes... An orange, a couple fig newtons (i swear by it on tournament days), some trail mix, and a small sandwich. And lots of water. If its on the beach... Salt and vinegar chips and even more water (try pedialite if you're a cramper).
For breakfast... Coffee and a breakfast sandwich from dunkin donuts. While high in calories, I plan on using that fat for energy later in the day.