Did you know that Southern Baptists tend to be the fattest Americans? Catholics are somewhere in the middle of the range; Jews and other non-Christians have the lowest average body weight. This from Fat Land - How Americans Became the Fattest People in the World
, which theorizes that the fundamentalist focus on other "sins" like smoking and oh, say, homosexuality encouraged their followers to turn to safe pursuits like wholesale gluttony. I don't know whether I buy it, but the book's a great, compelling read.