Michael Moss

Health messages are simply overwhelmed, in volume and in effectiveness, by junk-food ads that often deploy celebrities or cartoon characters to great effect. We may know that eating fruits and vegetables is good for us, but the preponderance of the signals we get - and especially the signals children get - push us in the direction of junk food.

The biggest hits - be they Coca-Cola or Doritos - owe their success to complex formulas that pique the taste buds enough to be alluring but don't have a distinct, overriding single flavor that tells the brain to stop eating.