Does food 'addiction' explain explosion of obesity?

July 10, 2007— -- Obesity has long been blamed on weak willpower, overeating, genetics and lack of exercise. Now scientists increasingly are seeing signs that suggest there may be an additional contributor: food addiction.

Monday night and again today, dozens of the nation's leading researchers in obesity, nutrition and addiction planned to discuss whether food has addictive properties for some people. They're gathering in New Haven, Conn., at a meeting sponsored by Yale University's Rudd Center for Food Policy and Obesity.

"We believe that there is sufficient science to suggest there is something to this, so we are bringing the leading authorities together to decide whether food addiction is real and what the underlying psychology and biology might be," says Kelly Brownell, director of the Rudd Center.

"It's surprising that our field has overlooked this concept for so long," he says. "Society blames obesity only on the people who have it and has been close-minded to other explanations."

Support for the idea of food addiction comes from animal and human studies, including brain imaging research on humans, says Mark Gold, chief of addiction medicine at the McKnight Brain Institute at the University of Florida, who is a co-chair for the meeting.

In a medical setting, "we evaluated people who were too heavy to leave their reclining chairs and too big to walk out the doorway," he says. "They do not eat to survive. They love eating and spent the day planning their new takeout choices."

Psychiatrist Nora Volkow, director of the National Institute on Drug Abuse, a speaker at the meeting, says the research in this area is complicated, but most people's weight problems aren't caused by food addiction.

Some studies focus on dopamine, a neurotransmitter in the brain associated with pleasure and reward. "Impaired function of the brain dopamine system could make some people more vulnerable to compulsive eating, which could lead to morbid obesity," Volkow says. She did groundbreaking research in this area while at the U.S. Department of Energy's Brookhaven (N.Y.) National Laboratory.