"Ron, you may not believe it, but I can actually see this as a good thing for a couple of reasons. First, you never met the muggles who raised me before I moved in with you, but they were really, really fat, and they were disgusting, and I never want to take a chance I'd end up looking like that. Also, I remember from my early schools, that exercise strengthens the body, and a stronger body means a stronger magical core, which is a good reason all by itself. Tell you what, at the end of the year, you and I will compare spells strength, and whoever has a stronger spell gets the Nimbus when we play Quidditch over the summer, deal?"