Up until comparatively recently the scientific consensus was that neurogenesis, the process by which new neurons are created and assimilated into the workings of the brain, simply didn't happen in adults to any significant degree. Fortunately we are supplied with a modest flow of new brain cells as life goes on, and this post is a reminder that, amongst all the other benefits caused by calorie restriction, it also increases neurogenesis. Eat fewer calories whilst still obtaining an optimal amount of nutrients and you gain more functional brain cells as a result:
Adult neural stem cells in the dentate gyrus of the hippocampus are negatively and positively regulated by a broad range of environmental stimuli that include aging, stress, social interaction, physical activity, and dietary modulation. Interestingly, dietary regulation has a distinct outcome, such that reduced dietary intake enhances neurogenesis, whereas excess calorie intake by a high-fat diet has a negative effect.
This has actually been known for at least a decade, as you'll see if you look back into the scientific archives. For example, this from 2000:
We found that maintenance of adult rats on a DR regimen results in a significant increase in the numbers of newly produced neural cells in the dentate gyrus of the hippocampus ... The increase in neurogenesis in rats maintained on DR appears to result from decreased death of newly produced cells, rather than from increased cell proliferation. We further show that the expression of brain-derived neurotrophic factor, a trophic factor recently associated with neurogenesis, is increased in hippocampal cells of rats maintained on DR. Our data are the first evidence that diet can affect the process of neurogenesis, as well as the first evidence that diet can affect neurotrophic factor production. These findings provide insight into the mechanisms whereby diet impacts on brain plasticity, aging and neurodegenerative disorders.
Or this from 2002:
We now report that neurotrophin expression and neurogenesis can be modified by a change in diet. When adult mice are maintained on a dietary restriction (DR) feeding regimen, numbers of newly generated cells in the dentate gyrus of the hippocampus are increased, apparently as the result of increased cell survival. The new cells exhibit phenotypes of neurons and astrocytes.
So what exactly does a modest increase in the creation of new functional brain cells mean for humans? That remains to be determined in detail, and seems to boil down to quantifying the effects of increased plasticity in the brain. There is the expectation in the scientific community that increased plasticity will be shown to be beneficial in a range of ways, but to date few lines of research have managed to definitively link changes in plasticity with cognitive ability, resistance to age-related neurodegenerative diseases, and so forth. That would seem to be just a matter of time, however.
Meanwhile, the benefits of calorie restriction are so broad and large - on a par with exercise in humans, and thus still better for healthy people than any presently available medical technology - that it would seem foolish not to give serious thought to trying it.