A new study seems to endorse what many nutritionists have long advised. Cutting calories may have a startling impact on memory retention.

Under the observation of a University of Münster neurologist and his colleague, subjects who cut their calorie intake by 30%, showed a 20% improvement in memory. Another group was advised to increase the amount of unsaturated fat they ingested by 20%, while keeping calories constant.  A third, control group made no changes to their diet. The latter two showed no significant changes in memory performance.  

The participants who'd increased the amount of fat in their diet were believed to show no signs of improvement because that fat was not from fish. Fish such as herring, sardines, albacore tuna, and salmon contain Omega-3 fatty acids which have been shown to help cognitive and behavioral function.