You’d think that telling someone not to do something would be simple—“don’t put your hand in the cookie jar.” But we all know how that story turns out. Why? Because the human mind plays funny tricks when you tell it not to do something. The brain—specifically the insula, the part that influences cravings—hears “don’t take the cookie” and reacts by stimulating cookie-cravings. It’s the same reason telling a little kid “don’t pull your sister’s hair” makes him want to do it that much more. A better approach when you want to curb a certain behavior: Flip the message. Instead of “Don’t eat cookies,” try “Do eat a cookie later, after you have your veggies.”