We always have breakfast in our room and usually a couple of dinners. Occasionally a lunch, but we do take picnics to the water parks also. WDW food has way too much sodium, not enough fresh fruits and veggies, and not enough lean protein. We try to eat healthier, even on vacation and our DVC kitchen helps us do that. It's also way too expensive, and we are also usually there for at least two weeks, plus time at the beach, Universal, etc. so we do not like eating every meal out.
We aren't that big on theme park food, and no matter how much WDW tries to convince you otherwise, their food lacks in many ways, including flavor. Some of the overpriced garbage they try to pass of as food is disgusting, though we do split a funnel cake once a year.
We always have yogurt, fruits and veggies (although we are used to California produce and Florida is lacking in that area), whole grain breads, cheese, and cereal for breakfasts. We make sandwiches or salads for lunches or dinners. When we used to stay in 1bedrooms (when the kids came with us), we used to cook spaghetti, baked chicken, tacos or burritos (though it was really hard to find tortillas in Florida back in the day), or mac & cheese. We don't use convenience foods, but we never spent more than 20-30 minutes making dinner. We have found Publix to be the grocery store that is most like what we have here in California as far as fresh produce.