Different patterns of memory impairments accompany short- and longer-term maintenance on a high-energy diet.

Intake of diets high in saturated fat and simple carbohydrates is associated with cognitive impairments in both humans and rodents. Here we report that feeding rats this type of high-energy (HE) diet has different effects on different types of learning and memory processes. Rats were first trained to solve spatial and nonspatial reference (RM) and working (WM) memory problems in a radial maze paradigm. Memory retention was assessed following six durations of free access to an HE or standard chow control diet ranging from 72-hr to 90 days. The results showed that performance on spatial RM and WM was impaired following only 72-hr on the HE diet and that the magnitude of the spatial RM and WM retention deficits were stable across all tests. On the other hand, stable deficits in nonspatial RM and WM emerged only after 30 days on the HE diet. The results suggest that the processes underlying spatial memory may be especially sensitive to disruption following intake of HE diets.