NursingLink

News >> Browse Articles >> General Health

News >> Browse Articles >> Medical Research/Science

When Unhealthy Foods Hijack Overeaters' Brains

Former FDA Commissioner David Kessler holds up a piece of carrot cake at a bakery. Kessler has a new book out on addiction-like overeating. (AP Photo/Eric Risberg)

At issue is how the brain becomes primed by different stimuli. Neuroscientists increasingly report that fat-and-sugar combinations in particular light up the brain’s dopamine pathway — its pleasure-sensing spot — the same pathway that conditions people to alcohol or drugs.

Where did you experience the yum factor? That’s the cue, sparking the brain to say, “I want that again!” as you drive by a restaurant or plop before the TV.

“You’re not even aware you’ve learned this,” says Dr. Nora Volkow, chief of the National Institute on Drug Abuse and a dopamine authority who has long studied similarities between drug addiction and obesity.

Volkow is a confessed chocoholic who salivates just walking past her laboratory’s vending machine. “You have to fight it and fight it,” she said.

Conditioning isn’t always to blame. Numerous factors, including physical activity, metabolism and hormones, play a role in obesity.

And the food industry points out that increasingly stores and restaurants are giving consumers healthier choices, from allowing substitutions of fruit for french fries to selling packaged foods with less fat and salt.

But Kessler, now at the University of California, San Francisco, gathered colleagues to help build on that science and learn why some people have such a hard time choosing healthier:

_First, the team found that even well-fed rats will work increasingly hard for sips of a vanilla milkshake with the right fat-sugar combo but that adding sugar steadily increases consumption. Many low-fat foods substitute sugar for the removed fat, doing nothing to help dieters eat less, Kessler and University of Washington researchers concluded.