It could be possible to train your brain to prefer lighter low-calorie foods. 

A brain scan of adult men and women suggested it is possible to combat the addictive power of unhealthy foods while increasing the preference for healthier ones, Tufts University reported. 

"We don't start out in life loving French fries and hating, for example, whole wheat pasta," said senior and co-corresponding author Susan B. Roberts, Ph.D., director of the Energy Metabolism Laboratory at the USDA HNRCA, who is also a professor at the Friedman School of Nutrition Science and Policy at Tufts University and an adjunct professor of psychiatry at Tufts University School of Medicine. "This conditioning happens over time in response to eating - repeatedly! - what is out there in the toxic food environment."

To see if this cycle could be combated researchers studied the reward system in 13 overweight and obese individuals, some of which were enrolled in a Tufts University weight loss program.

Both groups underwent magnetic resonance imaging (MRI) scans at the beginning and end of a six-month period. The brain scans in those enrolled in the weight loss program revealed changes in areas of the brain's reward center associated with learning and addiction. After the six month period the region showed a higher sensitivity healthy low-calorie foods and a decreased sensitivity to unhealthy foods. 

"The weight loss program is specifically designed to change how people react to different foods, and our study shows those who participated in it had an increased desire for healthier foods along with a decreased preference for unhealthy foods, the combined effects of which are probably critical for sustainable weight control," said co-author Sai Krupa Das, Ph.D., a scientist in the Energy Metabolism Laboratory at the USDA HNRCA and an assistant professor at the Friedman School. "To the best of our knowledge this is the first demonstration of this important switch."

The findings were published in the journal Nutrition & Diabetes.