The brains of mice fed a high-fat diet for an extended period of time showed irreversible changes in areas associated with reward and pleasure, a new study has found.

The research was presented at Neuroscience 2010, the annual meeting of the Society for Neuroscience, held in San Diego.

"Our data show that chronic consumption of a high-fat diet leads to significant changes in brain chemistry," said senior author Teresa Reyes, PhD, of the University of Pennsylvania, School of Medicine.

Fatty foods tap the pleasure centers of the brain, the same areas triggered by cocaine or heroin. Reyes and her colleagues explored whether these pathways could be modified on a molecular level by eating a high-fat diet for a long period of time. The researchers found that the genes involved with reward were altered in mice fed a high-fat diet for more than six months. The authors suggest the changes, which may promote cravings for fatty foods, could have far-reaching consequences.

Many people struggle with unhealthy cycles of weight loss and gain. This study illustrates the biological challenges of breaking out of this cycle. "These results provide further insight into the health consequences of long-term, high-fat diets, and suggest one explanation for why some people face such difficulty in the path to weight loss and healthier eating," Reyes said.

Research was supported by the National Institute of Mental Health.