You do not need to have any sort of doctor's note to bring food into the theme parks. There are many, many people who bring both food and beverages into the WDW theme parks every day for medical or budgetary reasons, or simply because of personal preference. There are no restrictions about the type of food
you can bring to the park with you. However, you should
be aware of that alcoholic beverages may not be brought into the parks.
Nor are glass containers, other than baby food jars, are allowed.
While you can bring any food you want to WDW, there are some
restrictions about how you transport food into the parks. Large coolers
and wheeled coolers are not permitted. If you click
here,
you'll find a list of Frequently Asked Disney parks questions. At the
bottom of the list, you'll see the maximum dimensions of coolers
allowed in the parks. As long as you stay within
these guidelines, you can enjoy your own food in the theme parks.
Have a wonderful visit to Walt Disney World.