Working to be in shape again  aka going to the gym  That wouldn't be working on getting in shape (again? Yeah, right. It's referring back to early childhood). For a fat, "working" on something means preparing to do it. So in this case, it's shopped for workout clothes it will buy and noticed a gym on the way to McBeetus that it has convinced itself it would would join sometime in the future. It's a wonder it isn't slim already! Wow, this is hard to maintain. Diets don't work, guess it'll have to give up. At least it tried! /s