One such longevity pathway is FOX03, which, among
other things, helps to maintain stem cell pools in the body as
we age.^8 Stem cells are cool because they are able to
differentiate into many different cell types—including
neurons—and help to repair against damage incurred during
aging.^9 Some scientists believe that if we could “top off,” or
at least slow depletion of, our diminishing stem cell pools as
we get older, we’d be able to better defend against the
ravages of aging and extend our years spent youthful and
healthy. Activating FOX03 may be one of the most readily
accessible ways of doing this. In fact, people with one copy
of a gene that makes their FOX03 more active have double
the odds of living to be one hundred years old. (Those with
two copies have triple the odds!)^10
The empowering news here is that we can mimic many
of these benefits in part by keeping tight reins on our
bodies’ production of insulin. We can do this by engaging
in brief periods of fasting (which I will introduce in chapter
6 ), avoiding rapidly digesting sugars, and demoting starches
(especially processed grains) from mainstays in our diets to
occasional indulgences.^11 (Genius Food #9—wild salmon—
also contains a compound that stimulates FOX03.)
Gumming Up the Works
You may already be familiar with some of the cognitive
consequences of regular insulin spikes—I certainly was. The
most obvious symptoms may be the lethargy that you feel