France’s pervasive and strong food culture makes it possible for its people to eat relatively unhealthy food yet remain very healthy. Unwritten social rules do what expensive pills and diet fads have been unable to do in the United States.

Would you drink less soda if it cost a little more? Lawmakers believe that a tax on sugary carbonated beverages can go a long way toward combating America’s obesity epidemic. There’s just one problem: it won’t work.