I tend not to eat much at parks these days, mostly because the food & drink are WAY overpriced, but also to make sure I can keep coaster-riding without any gastro tract upsets
I know a lot of people can eat & eat & eat and feel nothing from all the riding, but I had a hamburger once at SFMM just before going on Riddler's Revenge, with all its inversions, and then Viper, and I felt kinda weird in the stomach for several hours afterward..
Usually I'll eat a light breakfast before heading out to the park, and then drink sodas & water periodically during the day, and then after finished riding, I'll have a nice big dinner (well-earned after all that walking & standing in line!)- outside the park.