Dr Maxime Cournot, who headed the study, suggested that hormones secreted from fats could have a damaging effect on cerebral cells, resulting in decreased brain function. "Another explanation could be that since obesity is a widely known cardiovascular risk factor, due to the thickening and hardening of the blood vessels, that the same happens with the arteries in the brain," said Dr Cournot, an assistant professor in clinical epidemiology at Toulouse University Hospital.