Jay Richards, author of Eat, Fast, Feast: Heal Your Body While Feeding Your Soul―A Christian Guide to Fasting, found that almost the first benefit of fasting, after a day or so, was mental clarity. Why would that be? Surely, fasting would make us dizzy, unfocused, constantly obsessed with visions of food. But then again, maybe not. He suggests,
Assume you wanted to design the human metabolism for survival over the long haul of human history. Isn’t this how you’d do it? After all, our brain is our most important survival organ. What if the brains of early humans slowed down and their thoughts scattered to the winds whenever they missed a meal or two—just when they most needed to hunt and forage for food? This trait would have gotten weeded out of the gene Eat, Fast, Feast pool after a few centuries of erratic food supply. Since we’re still here, we can assume that our ancestors enjoyed some metabolic way to survive the frequent bouts of scarcity. And we have inherited the same metabolic system, even if we rarely need to use it in the twenty-first century.
Excerpted from Mind Matters