Simply ejecting your rear from the couch means your hand will spend less time digging into a bag of chocolate chip cookies. That is the simple but profound finding of a new Northwestern Medicine study, which reports simply changing one bad habit has a domino effect on others. Knock down your sedentary leisure time and you’ll reduce junk food and saturated fats because you’re no longer glued to the TV and noshing. It’s a two-for-one benefit because the behaviors are closely related.