Research on food and addiction is in its infancy. New studies however are suggesting that overeating may dampen your dopamine response, which can make you overeat even more.

Dopamine is a neurotransmitter that motivates us to eat (and enjoy other “rewarding” behaviors).  In 2001, Nora Volkow and her colleagues at the Brookhaven National Laboratory published a groundbreaking study called “Brain Dopamine and Obesity.”  The study found that very obese people had lower levels of dopamine in the “reward” areas of their brains than did people who were normal weight.  “These brain scans were game-changers,” according to Pamela Peeke assistant clinical professor of medicine at the University of Maryland School of Medicine. “Because this is precisely the same thing that happens in meth heads, cocaine addicts, alcoholics, and other addicts.”  So, if dopamine makes you want to eat or take drugs, why then do obese people or drug addicts have less of a dopamine response?  “We used to believe that people were addicted because they were more sensitive to rewarding effects,” says Volkow.  “We thought they had more dopamine release, that it would be more pleasurable.”   ” However, it’s the opposite.”

Researchers have wondered if some people overeat because they are born with a dopamine system that does not respond.  Or, is it possible that obese people have a low dopamine response because they overeat and overstimulate their dopamine?  It may be both.  In a study of 26 overweight and obese young women, those who gained weight over six months had less response in the brain targeted by dopamine when they drank a milkshake than they had six months earlier.  The young women also showed a reduced dopamine response compared to the overweight women who had not gained weight.  A lower dopamine response may not only make it more likely to overeat, but to dampen the dopamine response even more.

So which foods can be addictive? According to Kyle Burger, a researcher at the Oregon Research Institute, those foods that are sweet, fatty and have a lot of calories –  no surprise.  “It looks like the habitual consumption of food – specifically calorie – dense food – can elicit changes in brain responses that mirror drug addiction,” ways Burger.  However, as humans we all crave certain foods…. and craving is not addiction.  Craving is an intense desire to eat a particular food.  Some studies show that among college students, approximately 60% of women crave sweet foods that are usually high in fat, while men’s sweet cravings are at about 40%.

Food addiction research is in its early stages.  The hope is to continue following people over a long period of time.  Says Burger: “The take – home message is that the frequent consumption of calorie – dense food may be altering your brain responses in a way that’s going to make you consume more.”    Nutrition Action   May 2012

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