Scientists have found evidence of inflammation and neuron injury in the brains of mice just days after eating foods high in fat, according to a study published in The Journal of Clinical Investigation. A long-term diet of similarly fatty foods left permanent damage in the rodents.

When the brain attempts to heal the injured neurons, gliosis results, which can leave scars on the central nervous system, says the study’s lead author, Dr. Michael Schwartz, director of the Diabetes and Obesity Center of Excellence at the University of Washington.

Researchers analyzed human MRIs during the study, and found that obese patients had higher levels of gliosis, suggesting that the same type of scarring may be occurring in humans.

These findings suggest that what we eat reprograms our brains, and provides a whole new approach to dieting, says Dr. Steven R. Smith, co-director for the Sanford-Burnham Diabetes and Obesity Research Center, who wasn’t involved in the study.