Pricey organs: Liver beats the brain for energy usage.

Yesterday, a friend of mine made a crazy claim; that the liver used more energy than the brain. Crazy because the brain always gets the credit for being the big energy hog. So I looked it up.

I found the energy usage by mass for the heart, kidneys, brain, and liver on Google Books. I got the masses of those organs from wikis and such. The result:

	kilocalories/kg/day	kg	kilocalories/day
Heart	610	* 0.3	= 183
Kidneys	390	* 0.3	= 117
Brain	296	* 1.4	= 414
Liver	290	* 1.5	= 435

So it's liver FTW!

Of course, there's error in those numbers, and each will fall somewhere in a range, but still. Quite unexpected.

Aside: Those numbers mean ~40% of the body's energy is used just by the brain and liver. ~55% by those four organs.

Aside #2: That Google Books link had another interesting fact. The brain in a newborn baby uses 74% of its energy!! Wow.