Cutting calories by 30% for three months has boosted memory and reduced insulin concentrations in a group of healthy elderly people. Previous research on the possible benefits of calorie restriction has yielded mixed results. Some studies have found no benefits. Others have found that calorie restriction protects rats and mice against age-related memory loss and some neurodegenerative diseases. In humans, cutting calories has been linked to prolonged health, but there have been no previous reports of an effect on memory.
Now, neurologist Agnes Flöel and her colleagues at the University of Münster in Germany have filled that gap. The group looked at 50 people divided into three groups: one maintained its usual diet, one was told to cut calories and the third was was asked to eat more polyunsaturated fatty acids — nutrients found in foods such as fish and olive oil that have previously been linked to reducing the risk of cognitive impairment. The participants were either of normal weight or overweight, and averaged just over 60 years old.
Three months later, the researchers found that those who cut calories were 20% better at remembering a list of words than those who either maintained the same diet or ate more polyunsaturated fatty acids.