University of Cambridge, UK
A comparative cognitive scientist considers the effects of high-calorie diets on the brain.
It is well established that an excessive intake of high-calorie foods, unless coupled with plenty of exercise, leads to obesity, which is a growing public-health concern. As a dancer and a scientist, I am well aware of the intimate connection between the body and the brain, and not at all surprised by the recent accumulation of evidence showing that a high-calorie diet leads to a suite of cognitive impairments, particularly in memory. What is striking, however, is how quickly the effects can occur and how selective they are.
Scott Kanoski and Terry Davidson at Purdue University in West Lafayette, Indiana, studied the effects of a high-energy diet on the memory performance of rats trained in a radial-arm maze (S. E. Kanoski and T. L. Davidson J. Exp. Psychol. Anim. Behav. Proc. 36, 313–319; 2010). They found that maintaining rats on a high-energy diet for just 72 hours was sufficient to result in a marked impairment in spatial memory. Deficits in non-spatial memory took much longer to detect, emerging only after 30 days. Spatial skills are therefore particularly vulnerable.
This finding has important implications for our own lifestyle. Clearly, consuming an excessively high-calorie diet can result in marked decreases in cognitive abilities, especially in spatial memory. The fact that this occurs in such a short space of time, prior to any significant gain in body weight, suggests that diet-induced cognitive impairments could contribute to, rather than simply be a consequence of, obesity. So hide the high-calorie foods — if out of sight is out of mind, it might just save your brain!