The human brain uses 20% of the body’s energy even though it’s only 2% of the body’s total weight.

Matthews, Scott. 1144 Random, Interesting & Fun Facts You Need To Know

I suspect that some of us use a lot more or a lot less than 20%. I kinda think that those of us who don’t have much hair on top of our heads is because it was all burned off by the heat coming off our brains. 😎 Or maybe it is because we are hot heads!!