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It may be possible to train the brain to prefer healthy foods, according to research by scientists at Tufts University and at Massachusetts General Hospital.

A brain scan study in adult men and women suggests 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,” said Susan B. Roberts at Tufts University.

“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 cravings and temptation.

Roberts and colleagues studied the reward system in 13 overweight and obese men and women, eight of whom were participants in a new weight loss program and five who 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 centre associated with learning and addiction.

After six months, this area had increased sensitivity to healthy, lower-calorie foods, indicating an increased reward and enjoyment of healthier food cues. The area also showed decreased sensitivity to the unhealthy higher-calorie foods.

The weight loss program is specifically designed to change how people react to different foods, and the study shows those who participated in it had an increased desire for healthier foods along with a decreased preference for unhealthy foods.

The authors hypothesise that several features of the weight loss program were important, including behaviour change education and high-fibre, low glycemic (GI) menu plans.

“There is much more research to be done here, involving many more participants, long-term follow-up and investigating more areas of the brain,” Roberts says.

“But we are very encouraged that the weight loss program appears to change what foods are tempting to people.”

The research is published in the journal Nutrition and Diabetes.

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