Research published January 22, 2014, online in the American Journal of Clinical Nutrition studied food addiction among 134,175 middle-aged and older women who participated in the Nurses' Health Study. Slightly more than 8% of women aged 45-64, and 3% of older women, meet the criteria of being addicted to food.

Researchers say, for the first time in a large, U.S.-based population of women, they have documented the pervasiveness of food addiction by using the Yale Food Addiction Scale. The survey asks each participant to rate 27 questions about their eating habits over the past year, such as: I find that when I start eating certain foods, I end up eating much more than planned; and I find myself continuing to consume certain foods even though I am no longer hungry.

The women consumed hyperpalatable foods which are high in sugar, starch, fat, or salt. "When a person eats a hyperpalatable food, the brain releases a chemical called dopamine. Most people walk away satisfied. But for some the desire to repeat the pleasure is too strong to resist. This chemical produces a feeling of exhilaration or pleasure -- the "I've got to have it" feeling," says Kimberly Davidson, author of I'm Beautiful? Why Can't I See It? "We get immediate gratification and find our favorite food hard to give up, which is a good definition of addiction," Davidson added.