It’s true that dieting doesn’t work (“Let the post-diet era begin,” Health/Science, Oct. 1), because diets are not the problem. The real culprit behind America’s expanding waistline is our increasingly sedentary lifestyle. Technology such as elevators, cars, dishwashers, and fax machines allows people today to choose convenience over burning calories.

Practically ignoring this couch potato crisis, nutrition activists have sidetracked the obesity debate in search of a magical one-size-fits-all diet plan. But the National Weight Control Registry – the group that tracks the thousands of Americans who have effectively lost and kept weight off for more than a year – found no single formula for success among its members’ eating habits. In fact, the one theme they all have in common is physical activity.