What is the Fattest Organ in the Human Body?

April 21, 2024


An organ is defined as a self-contained group of tissues that perform a specific function in the human body. Some examples of organs are, of course, the heart, lungs, stomach, brain, kidneys, skin, and liver, to name a few. Which of these, or any of the other organs, are the fattiest? The answer may surprise you.

The brain is the fattiest organ in the body, coming in at 60% fat. Yes, you and everyone around you have a fat brain. The brain has about 100 billion neurons, and each one of these neurons has a thin, double-layered membrane composed of fatty acids. Fatty acids are one of the most important molecules that determine your brain’s ability to perform. Right there, the brain is becoming fatter.

Add to this the myelin sheath (a protective layer covering a nerve fiber, or axon, from a neuron), which is composed of 70% fat and 30% protein. Each neuron can have 10,000 to 100,000 of these connections with other neurons, with each fiber wrapped in a myelin sheath. You can see how these numbers can become astronomical and how the brain can be so fat. This is one time you don’t want a body part to be thin.

About the author 

Daniel Ganninger - The writer, editor, and chief lackey of Knowledge Stew, the author of the Knowledge Stew line of trivia books, and editor of Fact World and the Knowledge Stew sister site on Medium, our ad-free subscription sites. I hope you learn many new things here that add to your knowledge.

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