I'm in a little different situation from you, but have a related quandary I'm pondering. We've always been conflicted as it pertains to health and WDW. In the last couple of years, especially when it has been "just us," a WDW vacation, was very conducive to our health: We typically got a lot of exercise in, including miles of walking around the parks, bicycle riding, swimming, etc. We took advantage of the superior health club facilities, as well.
However, before we "got healthy" we used WDW as an excuse for gluttony (for lack of a better word). There are just so many superior choices, and they were all so fully devoted to presenting the most delectible, fattening dining experiences, that we'd often come home quite a few pounds heavier than we left.
While we're now healthy enough to not need to lose weight to enjoy WDW to its fullest, I am wondering to what extent we can add back some part of these wonderful dining experiences that we enjoyed so much years ago, without starting down a slippery slope. During our visits in late 2001 and early 2002 we didn't enjoy one meal out of our DVC villa. In mid 2002, we only did one meal, and that was a meal Chef Mary Ann made especially for us, to our strict dietary restrictions. This year, however, I don't want to run back to the room every day at noon for a salad with canned tuna and low-cal dressing.
So, I suppose I am a bit motivated to lose two or three pounds over the next few weeks, just to assure myself that I'm in enough control to let loose a little bit during our upcoming trip. By the same token (and this is really the main point), I'm not sure it is wise to "save up calories" to cover for over-consumption during our upcoming trip. :-\