Remember that your definition of medical need may differ from Disney's. They go to great lengths to ensure people with allergies can safely eat in their restaurants and food courts.
I did read of a woman who got Disney to agree to a microwave after discussing with the chefs the extent of her child's allergy, but the allergy was bad enough that they wouldn't be safe walking into a restaurant let alone eating in one. Very few have allergies that severe. Last time we were at Pop, we got talking with one of the chefs who was telling us about 2 of his daughters who are so allergic to lactose that they always start having a reaction just from walking into most pizza parlors. His daughters can safely walk into any food places at WDW.
My family has to deal with quite a few food allergies, but we still have a great time eating all over WDW because of how great they are about food allergies.
What specifically is your medical need?