Training your brain to prefer healthy foods.

• Position: Nutrition

It may be possible to train the brain to prefer healthy low-calorie foods over unhealthy higher-calorie ones, according to research at the Human Nutrition Research Center on Aging at Tufts University, Medford, Mass., and Massachusetts General Hospital, Boston. A brain scan study in adult men and women suggests that it is possible to reverse the addictive power of unhealthy food while also increasing preference for healthy foods.

"We don't start out in life loving French fries and hating, for example, whole wheat pasta," says Susan B. Roberts, director of the Energy Metabolism Laboratory and professor at the School of Nutrition Science and Policy at Tufts, who also is an adjunct professor of psychiatry. 'This conditioning happens over time in response to eating--repeatedly--what is out there in the toxic food environment."

Scientists have suspected that, once unhealthy food addiction circuits are established, they may be hard or impossible to reverse, subjecting people who have gained weight to a lifetime of unhealthy food cravings and temptation. To find out whether the brain can be retrained to support healthy food choices, Roberts and her colleagues studied the reward system in overweight and obese men and women, some of whom were in a new weight-loss program while others were in a control group and not enrolled in the program.

Both groups underwent magnetic resonance imaging (MRI) brain scans at the beginning and end of a six-month period. Among those who participated in the weight-loss program, the brain scans revealed changes in areas of the brain reward center associated with learning and addiction. After six months, this area had increased sensitivity to healthy...