Study Says Cars Make Us Fat

"Countries with the highest levels of active transportation generally had the lowest obesity rates," Bassett and Pucher conclude in the study published in the Journal of Physical Activity and Health. "Walking and bicycling are far more common in European countries than in the United States, Australia and Canada. Active transportation is inversely related to obesity in these countries."

http://blog.wired.com/cars/2008/12/surprise-people.html