Central heating--not sure if this is in her yet, but the obvious. The myth that Inuit have an extra bit of fat as insulation against the cold. A similar thing is said of swimmers to explain differences in body composition vs. other sorts of athletes, I've seen insulation as well as buoyancy suggested. But it's like saying that running marathons makes you very lean because the guys who win them are very lean. Do marathons make you lean--or do people who carry less fat to start with tend to be the people who win marathons?

Childhood obesity--at least the kids are getting off the smokes.