Some live to eat and some eat to live

BUFFALO, N.Y., Oct. 15 (UPI) -- A University of Buffalo researcher said obesity is part nature and part nurture -- influenced by genotypes that affect the neurotransmitter dopamine.

"Behavior and biology interact and influence each other," study leader Leonard Epstein said in a statement. "The genotype does not cause obesity; it is one of many factors that may contribute to it. I think the factors that make up eating behavior are in part genetic and in part learning history."

The study differentiates between food's reinforcing value, defined by how hard someone will work for food, from the "feel good" pleasure people get from food.

The genetic variation linked to a lower number of dopamine receptors is carried by about half the population, Epstein said.

The study, published in Behavioral Neuroscience, found obese participants clearly found food more reinforcing than non-obese participants and concluded that food is a powerful reinforcer that can be "as reinforcing as drugs of abuse."

Those with more dopamine receptors more easily experience reward and may need to consume less of a rewarding substance -- such as drugs or food, the study found.