When we went in the end of March, we ate breakfast in the room, fruit, granola bars, cereal, snacks and definitely water, but the big question that I had the whole time during our stay was this: Disney says that no outside food is to be brought in and they have people checking bags, so why are there so many people in the parks eating chips, sandwiches, drinks, ect, that are obviously brought from the outside it didn't add up then and it still doesn't make sense?!? It was my understanding that the only thing Disney allows from the outside is bottled water, which you absolutley must bring, because the water in Orlando tasted horrible!! I also suggest ordering the kids meals, often it is the same amount, at Pizzafari in the Animal Kingdom, the kids meal comes with an individual pizza, small bag of chips, and small drink. the Pizza is the same size as the one you can order for adults. Check around at the counter service restaurants, because you can save money with the kids meal if you do not have a huge appetite.
Have fun and Enjoy!