I found the food decent albiet expensive inside the park. Typical amusement park food such as pizza, burgers, chicken etc. There is a Panda Express on the lower lot.
If you plan on being there all day and night then the all you can eat meal plan is the way to go. Its about $20 or so and you can eat most anything you want whenever you want during the day. We did this last trip and it saved a bunch. We ate breakfast, lunch and dinner for $20/person.
The meal plan does not include drinks but they do sell mugs for about $7 that allows $1 refills all day.