Via the ringleader.
Professor Charles Courtemanchey of Washington University in Saint Louis not only has a cool name, he's also got a fascinating research result (PDF):
A causal relationship between gasoline prices and obesity is possible through mechanisms of increased exercise and decreased eating in restaurants. I use a fixed effects model to explore whether this theory has empirical support, finding that an additional $1 in real gasoline prices would reduce obesity in the U.S. by 15% after five years, and that 13% of the rise in obesity between 1979 and 2004 can be attributed to falling real gas prices during this period. I also provide evidence that the effect occurs both by increasing exercise and by lowering the frequency with which people eat at restaurants.
Hmm cool name indeed. French name I'd say. So he's got the time series, how about the cross section. In the USA gasoline is absurdly cheap and people are fat. OK
But the really interesting application is the mysterious fat states for Bush fact. Self reported obesity is significantly positively correlated with votes for Bush. Red states are more car friendly and would require pedestrians to walk a long long way. Hmmmmm. There have been huge changes in prices at the pump in non US developed countries due to excise tax increases. This is the way to test his model (the world price of oil is a world price and correlated with world trends in video game technology and high fructose corn syrup.
I know where the data are. Hmmmm. maybe ....