The brain can be trained to prefer healthy food over unhealthy high-calorie foods, using a diet which does not leave people hungry, suggests a study from the US.
Scientists from Tufts University say food addictions can be changed in this way even if they are well-established.
They scanned the addiction centre in the brains of a small group of men and women.
The results showed increased cravings for healthy lower-calorie foods.
Prof Susan B Roberts, senior study author and behavioural nutrition scientist at the Boston university, said:
"We don't start out in life loving French fries and hating, for example, wholewheat pasta.
"This conditioning happens over time in response to eating - repeatedly - what is out there in the toxic food environment."
Scientists know that once people are addicted to unhealthy foods, it is usually very hard to change their eating habits and get them to lose weight.
But Prof Roberts' research, published in the journal Nutrition & Diabetes, suggests the brain can learn to like healthy foods.