Can't stop eating? Blame your dopamine

By Maggie Fox, Health and Science Editor

WASHINGTON (Reuters) - People who just can't stop eating may be able to blame their genes, at least in part, U.S. researchers said on Monday.

They said up to 50 percent of the population carries a gene variation that may give them extra pleasure from eating -- and may explain why they are willing to work twice as hard for snacks as the other half of the population.

The gene affects dopamine, an important message-carrying chemical, or neurotransmitter, associated with behavior and movement.

"This gene is not just associated with overeating," said Jennifer Temple, a neuroscientist at the University at Buffalo in New York who worked on the study.

"It has been associated with drug addiction, alcohol abuse, gambling. It is associated with reward decisions," Temple added in a telephone interview.

Writing in the journal Behavioral Neuroscience, Temple and colleagues described an experiment in which they gave people access to many tasty snacks, including chips and chocolate.

Their volunteers thought they were taste-testing the food, but Temple's team watched to see who ate the most.

They also ran genetic tests on their 74 unwitting volunteers, looking for variations in two genes that affect dopamine levels.