Diet pills Harry Potter magic?

It's Harry Potter time, with the release of the final book in the 7-part series, and the 5th movie, so the movies are 2 books behind. I like fantasy myself, but haven't had a chance to read any of these books, but I have to wonder how they've become to popular. I mean, they were written for children, and I don't think I've ever seen children's books become so popular with everybody. Children, of coruse, yes. But adults who are reading him for the first time? There are adults who are fans of various children's fantasies, but the vast majority of them read the books as a kid, not first as an adult. I wonder if some are not just after some cheap magic spells -- like taking diet pills to lose weight like a miracle cure.