Turns out our cars might be making us fat, according to a study by the American Journal of Preventive Medicine (via Freakonomics). The study examined the BMIs of people who ride a new light rail system in Charlotte, N.C. were 81 percent less likely to become obese than car-driving (what's the word for people who live in Charlotte? Charlottans?) and cut their BMIs by an average of 1.18 kilograms per square meter. That translates to about 6.45 pounds for a person who's 5'5".
What's interesting is that the obesity-car connection also appears to work the opposite way: As America has gotten fatter, so have our cars. A 2009 study by the nonprofit Resources for the Future highlighted by the Consumer Reports Cars Blog found that from 1999 to 2005, a 10-percent increase in overweight and obese drivers coincided with a 2.5-percent decrease in the average fuel economy of the cars people sought out.
Unsurprisingly, that falling fuel economy coincides with the American love affair with the "light truck," as SUVs and pickup trucks are known in the world of government statistics, in the late 1990s and 2000s. As you can see in the chart, the adoption of trucks and SUVs also tracked with the rise of obesity to an amazing degree.
Of course, correlation isn't the same as causation, but intuitively it makes sense: Bigger people understandably want bigger vehicles, and bigger vehicles generally mean SUVs, pickup trucks and worse gas mileage.
What do you think? Does driving make people fatter? And does being fatter have something to do with the rise of bigger vehicles in the U.S. Or is it just a coincidence that these two phenomena coincided so closely?