The human brain, while at rest, uses about 20 percent of a person’s total energy intake.

Quick Scoop

Even when you are just sitting quietly, your brain is extremely metabolically active and constantly burning fuel.

For the average adult in a resting state, this adds up to roughly 20 percent of the body’s total energy use, despite the brain making up only about 2 percent of body weight.

Why it’s such a big energy user

  • The brain is always “on,” maintaining basic functions, consciousness, and readiness to respond.
  • Neurons are constantly sending and resetting electrochemical signals, which is energetically expensive.
  • Vision and hearing areas tend to use more energy than regions associated with smell and some types of memory.

Fun perspective

If you eat a standard day’s worth of calories, about a fifth of that goes just to keeping your brain running—even if the rest of your body is mostly resting.

TL;DR: The human brain is metabolically active and uses about 20 percent of a person’s energy intake while at rest.

Information gathered from public forums or data available on the internet and portrayed here.