Hi Ashli!
The Princess Half Marathon is a great race! I think you're going to love it, and it will be extra magical since it's your first visit in a long time:)
The good news is that there are some great healthy options all over Walt Disney World Resort. Plus, with the Disney transportation at the resorts, you can travel around the property easily.
I suggest taking a look at
Downtown Disney for some dining options. I love eating at Portobello, Paradiso 37 and Raglan Road. These are all great restaurants that offer a wide variety of choices, and you don't need a ticket to go to Downtown Disney.
Other choices that don't require theme park tickets would be the Resort restaurants. My favorite is
'Ohana at the Polynesian Resort.
If you will have park tickets, I suggest looking at the
World Showcase Pavilion inside Epcot. Not only is this a great place to find a good meal, but it is also one of my favorite spots at Walt Disney World for just walking around, sightseeing, and browsing!
I hope these suggestions help! Please let me know if you have any other questions.