Sometimes a scientific paper makes me giggle. The paper by Charles Courtemanche which I’m skimming this morning has a few examples of this. For example it says that people tend to under report their weight and over report their height; but more the former than the latter. It also includes this phrase “the food variables are left-censored at zero” – which means to say that the French fries don’t come out of your mouth, they only go in. This formula where on term is aproximately salads and another term is meatloaf is a hoot.
I don’t know were this guy get’s off announcing that meatloaf isn’t health! The author took two large data sets, one for prices (that’s gas price in the formula) and one for health behaviors. The health behavior data he used is collected by the Behavioral Risk Factor Surveillance System of the CDC. It’s a telephone survey conducted by state health departments. That survey is full of interesting facts, for example here is a map showing the states and metro-regions where people lack health insurance.
In anycase, he was looking to see if there was some corrolation between gas prices and obesity; and yes cheap gas makes us get fatter. Given that the next question is “How so?” The behavior data has lots of info about various things people are doing he can look for patterns there too. Thus we can can learn the valuable and amusing fact that “A rise in gas prices appears to increase the frequency of hamburger consumption…” and “a small increase in salad consumption”. From now on when ever I see that the price of gas has gone up I’m going to think “hamburger?” Generally higher gas prices don’t lead to healthier eating.
People lost weight when gas prices rose for two reasons. Where they ate changes; they ate more at home. And they walked more. I.e. higher gas prices reduced driving; displacing driving to the resturant and increasing walking as a substitute.
In this paper, I provide evidence of a causal link between gasoline prices and body weight. Using data from the BRFSS, I find nd that a $1 increase in gas prices would, after three years, reduce U.S. obesity by approximately 15%, saving 16,000 lives and $17 billion per year, a magnitude which offsets 16% of fuel consumers’ additional expenses. I also estimate that 13% of the U.S.’s rise in obesity over the period 1979-2004 can be attributed to falling gas prices during that time. Finally, I find that a rise in gas prices increases exercise and decreases the amount people eat out at restaurants, explaining their effect on weight.
This paper is actionable on a personal level. Lose weight, buy a gas guzzler! But then it is probably twice as effective to buy a car you hate.