I am ALWAYS watching what I eat, and I typically work out for at least an hour 3-4 times a week. So, although I used to worry about gaining weight at WDW, I've found that I really don't gain any weight at all. I really don't "go crazy" or overboard with what I'm eating while at WDW. I don't eat whatever I want just because I'm on vacation. I would say that my caloric intake is a bit more than when I'm at home, but it's because I'm constantly on the go when at WDW. The walking from morning till night will allow you to get your cardio in! So, if you just pay attention to what you are eating you will be fine.