Haven't we always known that sitting in a car in rush hour traffic is bad for your health? Well, somebody has gone to the trouble to pull together the stats showing that "active transportation" seems to help prevent obesity. Nations with a leaner population use more bikes, walk more, take more public transit. And bikes and walking both depand on renewable energy.
Of course, it's small, generally flat countries in Europe that have the healthier populations and more people who walk or bike. Netherlands. Sweden. Latvia. They also have smaller cities that do not spread into suburbs ringed by exurbs. I would suggest that much of the American dependence on autos is linked directly to how our cities and our endless suburbs are laid-out. Unplanned sprawl adds to the expense of providing public transit. Amsterdam or Stockholm are compact cities compared to Miami or San Diego, not to mention metro areas like Denver, Sacramento or Houston.