There is a small but growing body of science that relates low caloric intake with longevity and cognitive health. In other words, the slowing of aging and the preservation of memory.
The studies are taking place in the lab and with animals. This science is at the molecular level - or way under the skin - in the cells and in the brain. We don't know if what these studies show will carry over into human biology, but it is worth a shot.
Because there seems to be a correlation between caloric restriction and memory enhancement, scientists have searched for the particular mechanism that might be responsible. Recent work has focused on a protein, CREB1 - which is also a gene and a molecule - I think. It is a protein associated with memory. Something happens in lab mice on a restricted diet that activates the protein. Creb1 does not act alone and more is not known than is known.
A recent study, attributed to a Dr. Pani, showed that mice who were fed 70% of their usual caloric intake responded by producing the protein. The production of CREB1 is at the heart of many anti-aging studies.
I wanted to mention this study in light of the one I mentioned a few days ago in which the VLCD or very low calorie diet in one study meant only 890 calories per day.
The work of Dr. Giovambattista Pani implies a more doable strategy. Again, we do not know if the same result would occur in the human body, but most of us could stand to lose a few pounds anyway. If someone is consuming 2500 calories a day and dropped to 1750 - that is a reasonable reduction(with a doctor's go ahead of course).