The human brain is a fairly complex organ. It can best be described as the powerhouse of the body. It has allowed people to literally reach for the stars. Even though it is only about two percent of a persons weight, it consumes a hell of a lot more energy. To be as accurate as we possibly can be, the energy consumption of the human brain is about 20 percent of all the energy the body consumes. It translates into about 20 watts of energy, which is about the same as a household light globe.
That’s right, the human brain s a hungry little beast. It’s hunger is not only for information, but also for more than its fair share of energy. So how do we know that the human brain consumes about 20 watts of energy?
The average human body uses about 100 watts of energy. We know this by working out the average energy a person consumes in a day, which is 2400 calories. 2400 food calories is 2400 kilocalories. You then have to divide the KCal by 24 hours in a day which leaves you with 100 KCal per hour. The final part of the equation is to convert the KCal to watts, which several online converters will do for us, and gives us an answer of 116.3 Wh. Now remember we said the human brain consumes about 20 percent of the bodies energy? 20 percent of 116.3 Wh is 23.26 Watts, which is close enough to 20 watts for us.