Just in time for Earth Day, a new report claiming that fat people are responsible for global warming has been making headlines. Turning obesity into an environmental crisis is nothing new. (Newsweek documented similar “greener-than-thou” claims last year.)  So before we start mandating tailpipe emissions tests for every man, woman, and child in America, let’s take a closer look at this latest study’s logic.
According to the report in the current issue of the International Journal of Epidemiology, obese people are responsible for more greenhouse gas emissions than their slimmer neighbors partly because they are more prone to driving instead of walking. But the authors have the cause-and effect all wrong.  It’s not that obesity causes driving—it’s that driving, in part, causes obesity
Weight gain (or loss) is simply a matter of calories in versus calories out.  When people drive instead of walk, there are fewer calories going out, an imbalance that over time can lead to weight gain.
We looked at how transportation affects obesity in our report, Small Choices, Big Bodies.  Eighty-eight percent of Americans reported driving to work in 2000, up from 64 percent in 1960.  Each daily hour of driving increased the risk of obesity by six percent. But each daily kilometer walked decreased the risk of obesity by five percent. With more drivers and fewer walkers, it’s no surprise more Americans are carrying around some extra junk in their trunk.
It’s hard to think of a better occasion than Earth Day to appreciate our environment. Opt for a walk over a car ride, and go enjoy the spring air. It will help the environment – and your waistline.