Hello Heather, and welcome to the Disney Parks Moms Panel with a great planning question.
I am so happy to hear that you will be visiting the Walt Disney World Resort later this month. I can tell that you are probably in the midst of putting the finishing touches on your magical vacation. I am happy to tell you that you can bring any food into the parks that you would like. I usually carry snacks in my backpack or sling bag, but you are welcome to bring in whatever you like.
Keep in mind, there are no picnic areas in Disney Theme Parks and coolers of any size are not permitted. Backpacks are limited in size to no larger than 24" (61 cm) long x 15" (38 cm) wide x 18" (46 cm) high. I would also be mindful of what kind of containers you are using to carry your food. Security will not allow glass bottles or containers into the parks, with the exception of baby food jars. You can also
view the list of restricted personal items here.
Depending on the meals I have planned in advance, I find it is easier to carry fruit or prepackaged or bagged snacks like nuts or chips in my backpack. There are so many affordable dining options available that you will find the need to carry a lot of snacks is not necessary. I hope that answers your question. If you need any more help before you arrive, please come back and visit us again.
See ya real soon,
Andrea