I've been seeing more posts than ever on the boards these days about this. It's nice to see actually and all of these posts are great tips.
I am also extremely health conscious everyday as well. As of lately I've tried to cut out as much processed food as possible as well which is not easy. I also have a website that reviews the restaurants in WDW so that makes it even more tricky for us!
However that being said, here's what I do IN ADDITION to some of the tips others have mentioned (like stocking up on healthy snacks in your room, etc).
We eat at a lot of the TS restaurants so I practically study the menus before we go and pick a few of those options. I omit things from some of the dishes they serve or put things on the side...etc. If most of the choices are really in question, I'll go with the salad option.
We have become big fans of The Wave at the CR because a lot of their food is organic and health oriented AND DELICIOUS!
There are more restaurants like this popping up all over and even in WDW. Even some of the CS/QS are adding healthier options to their menus.
If you're stuck eating something that has a little more of what you really didn't want to eat, just eat less of it, don't beat yourself up and move onto the next plan. I know you mentioned you'll be in 4 different hotels, are some of these on property? There are places you can rent a microwave from in the area? Have you looked into that at all? We are big fans of the DVC studios and FW cabins so we have this option (the kitchenette of the DVC studios are wonderful and the cabins have full kitchens).
I'm right there with you and although we do occasional splurges in WDW but I try to stick to the healthier habits most of the time, so I totally understand. Best thing to do is the plan before you dine somewhere and to see what you're options are as far as being able to rent a microwave if you're in a regular hotel room.
One thing I have to add though because this always sticks in my mind since this happened in WDW. We went to R&C for lunch for my birthday some years back and they had this awesome salad, it was so great that I was looking forward to it the next trip and to my disappointment it was gone off the menu! I was so bummed, and there was nothing else similar, when I asked if they can just make a salad with chicken the server gave me attitude (like "why"), but she did return and said it was fine. When I asked her why they didn't have any "healthy" options on the menu, she shrugged her shoulders and the people next to me said (and I quote).."healthy? Why would you want to eat healthy in Disney World"... wow...I just shook my head in amazement.