About 3 weeks before our trip I decided that I wanted to get down to my "wedding day weight" so I lost 8 pounds. I get little exercise so I lost the weight by eating next to nothing.
We were at WDW for 10 days. We had at least one sit down, multicourse meal per day. Ate Mickey Bars, Dole Whip, crepes, Ghiradellis, snacked in the room. And walked walked walked walked every day.
Result: gained 1.5 pounds which is a tiny amount given all the food I shoveled in. Exercise is an amazing thing. (When we went to Paris last year, I actually lost 2 pounds.)