An elephant’s brain, at around a whopping 7,500 grams, makes our little 1,400 gram brain seem puny. The animal’s brain represents 1/550 of its total body weight while a human brain is about 1/40 of the total body weight. In other words, a human brain represents about 2.5% of the body weight while the huge grey guy’s brain is about .18 % of its body weight . That big brain is not so impressive now, huh?
While only representing a small percentage of our body weight, our brain uses 22% of the body’s energy expenditure even while at rest! Bottom line is: it takes an awful lot of calories to keep the human brain running. Thankfully, having such a large and powerful brain has allowed humans to develop the skills to provide a pretty constant food supply for it most of the time.
Our capability to evolve as a species was largely dependent on our ability to provide food for our brain on a regular basis. Imagine early humans migrating across the land, competing for survival among animals with smaller brains, but bigger teeth, sharper claws and much greater speed.
Our early ancestors had one advantage over the other animals that even our closest primate relatives didn’t have. We developed the unique ability to feed our brains with an alternative power supply other than direct food at frequent intervals. Some believe this to be the reason Homo Sapiens survived and the Neanderthals disappeared even though they had larger brains.
Superfuel For Your Brain
Normally, our brain is energized by steady stream of glucose delivered from glycogen, which is stored glucose primarily found in the liver and muscles. A regular supply of glucose is provided by breaking down muscle when necessary, not exactly a good thing for a hunter gatherer who may have to travel miles searching for food and go days in between substantial sustenance. After about three days without food, the liver starts to use body fat to create chemicals known as ketones which is a highly efficient fuel source for the brain and would’ve allowed our ancestors to continue hunting and functioning even when food was scarce. Ketones aren’t just fuel. They are superfuel.
In their book, Power Up Your Brain, David Perlmutter and Alberto Villaldo write:
Perhaps the most important dietary consideration related to optimizing the brain, enhancing neurogenesis, and providing a fertile environment for the process of neuroplasticity, so necessary for building new neural networks, is calorie reduction.
For this reason, in the book, they advocate reducing caloric intake and/or intermittent fasting. Fasting shifts the brain from using glucose as a fuel and turns on this alternate process. Fasting even reduces brain cell suicide (apoptosis), reduces brain inflammation, enhances detoxification, reduces free radical production and increases mitochrondrial replication and ability to generate energy. In the book, they go on to say:
Fasting is powerful medicine well beyond anything even remotely considered by modern pharmaceutical science. Indeed, the concept that dietary choices are healing is embodied in this famous quotation from the father of Western Medicine, the ancient Greek physician Hippocrates: “Let food be your medicine and medicine be your food.”
They define fasting as the abstinence of all food for a defined period of time at regular intervals. They do allow water and prescribe fasting in one day increments as outlined in the “Power Up Your Brain Program” in their book. Of course, they also stress that it is important to check with your physician before engaging in a fasting program. Reducing caloric intake on a daily basis will achieve the same desired effect they advise. Recent studies are also showing that fasting is beneficial in other ways as well.
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