You may not think about it much, but having a brain and using it requires a lot of energy.
Despite making up just 2 percent of the average adult’s body weight, the brain uses more than 20 percent of the body’s total energy. There’s no 80/20 rule at work here; the human brain is far and away the most energy-consumptive organ in the body.
And that’s not all.
According to brain studies, the amount of fuel needed for your brain is constant, meaning your brain is always hungry.