Whether you’re stressed or sad, food can also provide a quick fix by stimulating the brain’s pleasure/reward system, in which the neurotransmitter dopamine is released in response to pleasurable experiences involving, say, food, music or sex. Those rewards make us want to repeat a behavior again and again, says Nora Volkow, M.D., director of the National Institute on Drug Abuse at the National Institutes of Health in Bethesda, Maryland. “Dopamine is in charge of motivation. Drugs like cocaine use these same reward systems—only much more powerfully,” she explains. “In some people the compulsive pattern of food intake is so out of control that it mimics what you see in people who are addicted to drugs.”
Overeating to soothe emotions is also what behavioral scientists call a “conditioned” or “learned” response. When we repeatedly engage in a certain behavior every time we’re in a certain situation—say, grabbing a bag of chips at the vending machine every time we have a stressful meeting at work—we learn to associate one activity with the other. In the brain, the pleasure-inducing opioids that surge when you eat the chips work together with the dopamine system to make the experience more reinforcing, says Boggiano, “meaning that we are likely to want to do it again.” The more the behavior is repeated, the more ingrained it becomes; eventually just seeing the conference room door might trigger a powerful craving for Pringles.
“If you’ve always had something you do in response to stress, like eating, you keep on turning to it because that’s what you’ve practiced,” says Ramirez. “You’ve become ‘conditioned’ to that behavior. That kind of behavior might feel ‘addictive,’ but it’s not a true addiction.”