A study published in Nature found that intermittent fasting improved long-term memory, neurogenesis, and longevity (increased expression of Klotho) in mice. They found that intermittent fasting (every other day feeding) is superior to calorie restriction (10% less calories).
It’s unclear how well this relates to human adults, but it’s interesting to see the cognitive effects of intermittent fasting being studied (as opposed to weight loss).