se7enW
Back to Which
🏆 which

Which Organ Uses the Most Energy in the Human Body?

biologymedicine

Quick Answer

The brain consumes about 20 % of the body's total energy despite being only 2 % of body weight.

The Full Story

The human brain accounts for only about 2 % of body weight (roughly 1.4 kg) but consumes approximately 20 % of the body's total energy — about 400–500 calories per day. This energy powers electrochemical signals between roughly 86 billion neurons, maintaining consciousness, processing sensory input, and regulating bodily functions. The liver is the second most energy-demanding organ, followed by the heart (which beats about 100,000 times per day) and the kidneys, which filter about 180 litres of blood daily.

Key Facts

1.The brain uses about 20 watts of power — roughly enough to light a dim bulb.
2.Glucose is the brain's primary fuel; it cannot store energy and depends on constant blood supply.
3.About 60 % of the brain's energy is used to maintain the electrical charge of neurons at rest.

YouTube Angle

Suggested video title for this topic:

"The Hungriest Organ — Why Your Brain Eats 20 % of Your Energy"

Was this answer helpful?

Tap a reaction — it helps us pick what to cover next.