By Marissa Cevallos, HealthKey
April 5, 2011, 9:02 a.m.
To the food lovers who can't deny themselves an extra cookie (or 10): The problem may begin in your brain, where, scientists say, chemical surges affect your response to food, much in the way an addict responds to alcohol or drugs.

The possibility of food addiction has existed for some time. A new Yale study gives it a boost. In that research, scientists watched the brain activity of women tantalized, and then rewarded, with a chocolate milkshake. Their neural activity was similar to that of drug addicts, scientists said, as brain imaging showed activity surging in regions that govern cravings and falling off in those centers that curb urges.

High-fat and high-sugar foods tend to trigger the strongest reward responses in the brain, said the researchers, a feature that once would have helped our species survive. In America today, we don’t have as much of a problem finding high-calorie food.

Here, essentially, is what occurs in the brain of a drug abuser. Most abused drugs work by flooding the brain’s circuits with the feel-good chemical dopamine. The feeling is pleasurable, so the body wants to get the high again. But abused drugs overload the brain’s circuits, sometimes with two to 10 times as much dopamine as is derived from natural feel-good activities such as eating and sex. The brain adjusts to the overwhelming amount of dopamine, so the user needs more of the drug to achieve the same result.

Whether the desire for sugar-filled candy is truly similar to the craving to snort another white powder is uncertain. There’s evidence that rats can be addicted to sugar, demonstrating binge eating, withdrawal and craving. To a lesser extent, animals may binge on fatty foods too. That makes sense to anyone who has struggled to put the lid back on a Pringles can. But some psychologists argue that those results don’t apply to humans, and the evidence isn’t strong enough to say for sure that sugar addiction, or any other food addiction, plays a role in obesity and eating disorders.

Further, psychologists themselves are unsure how to think about overeating and, in particular, binge eating. Psychologists have been divided  on whether binge eating should be its own psychiatric disorder in the profession's’s diagnostic manual or included with anorexia and bulimia as an eating disorder. By a 2007 estimate, 2% of men and 3.5% of women experience symptoms of binge eating in their lifetimes.

Whether overeating is truly an addiction, some sufferers treat it as such. Overeaters Anonymous is modeled after the 12 steps in groups like Alcoholics Anonymous to help members recover from compulsive eating. Members are urged to eliminate foods that give them cravings, often processed foods with refined sugar.

If food is truly an addiction, that could open the door for interventions that work for drug addicts, such as medicine and behavioral changes. But overeating can often be a warning sign of overwhelming stress and larger emotional problems, and simply blaming it on the brain’s love of dopamine may be masking other problems. Trying to cope with a job loss, stress at work or relationship troubles can all trigger overeating.