Welcome to planDisney, Elizabeth!
You've asked a fantastic question, and the short answer is YES!
Guests are welcome to bring their own drinks and snacks into
Walt Disney World parks, as long as they abide by
Walt Disney World Resort Property Rules. For example, beverages brought to a theme park must be non-alcoholic and cannot be in glass containers. For the safety of the animals, if heading into Disney's Animal Kingdom Theme Park, those drinks may not include plastic straws.
Regarding
bringing food into the theme parks, you may certainly do so. In fact, we always bring small snacks for early morning arrivals and to hold us over between meals at the parks. Rope dropping at
Magic Kingdom Park so you can ride
Tron Lightcycle / Run first thing? Bring a cereal bar, granola bars, or even a PB & J to munch as you wait in line. Have a late breakfast scheduled but know the kids might get hangry before that early dinner? Fruit snacks, pretzels, bite-sized peanut butter sandwich crackers, granola bites, and even popcorn we popped in our Walt Disney World Resort hotel room's microwave can help anyone find the magic while they are between meals.
Elizabeth, my family and I fly down to WDW, but there are so many folks who bring sandwiches, cheese and crackers and such from home into the parks for their visits. You can do so, too! Be sure that your cooler bag meets the measurement requirement (no larger than 24" long x 15" wide x 18" high) with re-usable ice packs (loose or dry ice is not permitted), and those items will be good to go as well.
I advise everyone heading to WDW during the warmer months to bring a wide-mouthed refillable water bottle for each person in the group. There are
water bottle refill stations throughout the parks, so staying hydrated will keep everyone comfortable as they tour.
Elizabeth, as you plan your pixie-dusted days at The Most Magical Place on Earth, be sure to send additional questions our way. We love to help!
Andrea H