Your Brain Is An Energy Hog

Your brain is incredibly hungry and requires a huge amount of energy just to keep running. The human adult brain makes up about only 2% of the body’s mass yet uses 20% of energy intake. In children, the brain eats up 50% of daily glucose intake, and infant’s brains take a whopping 60%.

•     Brain sizes scale in proportion to body size with larger animals having larger brains, but on a per weight basis, humans pack in more neurons than any other species. This density is what makes us so smart. It takes an awful lot of fuel to power that complex brain, and there’s a trade off between body size and sustainable number of neurons. According to the Ted-Ed Animation, “A 25 kilogram ape has to eat 8 hours a day to uphold a brain with 53 billion neurons.”
•     The invention of cooking food gave humans the means to power their growing brains because our guts could more easily absorb energy from cooked food.
•     Our brains also adapted by learning to become incredibly energy efficient. At any one time, only a small proportion of brain cells are signaling, a process known as “sparse coding”, allowing the brain to use the least amount of energy while transferring the most information. The need to conserve energy resources is the reason that most brain processes happen below conscious awareness and that multitasking just doesn’t work. There’s not enough energy available to the brain to focus on more than one thing at a time.
•     The energy burden of maintaining an activation spike over the entire brain at once would be unsustainable. So, using the brain at full capacity all the time, like depicted at the end of the movie