I had a great turkey sandwich on multi-grain bread at the Plaza in the MK and DH had a nice strawberry salad there. (You may need them to modify the ingredients slightly, as I think it was supposed to have bacon on it.) The Plaza also had strawberry sorbet as a dessert option.
We also had a healthy meal at Beaches and Cream. DH had a great grilled chicken sandwich on multi-grain bun and I had a turkey sandwich again. They also offered fruit instead of fries for a side dish. DH had strawberry frozen yogurt, DS had orange sherbet, and I had fat free, sugar free vanilla ice cream (with full fat hot fudge on it!

) for dessert.
DH also fell in love with the strawberry frozen fruit bars that are sold at the ice cream carts in all the parks--only 50 calories each!
We also had a pretty healthy meal at the Cape May clam bake buffet for dinner--steamed clams, terriaki glazed salmon, corn on the cob, new potatoes, salad. The desserts here were very small. If you can stop at one or two you wouldn't do too much damage.
I was able to get the Sunshine Seasons in EPCOT to serve me a grilled chicken ceasar salad without the dressing. Most places are very nice.
Have a great trip!
P.S. Depending on your hotel, I would also suggest using the exercise room, if possible. We woke up EARLY so we could use ours at the Beach Club. I would go first and he'd stay with the kids. Then I'd come back and start getting ready for the day so he could go. Even 1/2 hr. is better than nothing, right?