This is Origin Stories, the Leaky Foundation podcast.

I'm Meredith Johnson.

Today on the show, our guest is Herman Ponsor.

Herman is an associate professor of evolutionary anthropology at Duke University.

He's a Leaky Foundation grantee who studies human evolution with a focus on how our bodies burn calories.

He's the author of the book, Burn.

This book and Herman's work blew my mind and it made me think about human evolution, human bodies, and life in a totally different way.

How are you doing?

Good. Hi Herman. Great to see you.

Yeah, good to see you too. Let's get going. I'm ready to do this.

To start with, can you explain what is metabolism?

Yeah, that's a great question. I think it's widely misunderstood.

So metabolism is the umbrella term for all the work that our cells do throughout the day.

And you know, you've got 37 trillion cells. Each one of them is a tiny little factory,

bringing nutrients in, carving those up, making other molecules, other proteins, sending those out

into your body.

So there's tons of work that each of those cells do, and that work requires energy.

In your book, you say that understanding metabolism is the key to understanding all living things,

including humans. Why is that?

If you want to know anything about any organism, then it's hard to think of a better place to start than how many calories it's burning and how it's spending that energy,

because energy is the currency of life.

And so everything we do, everything that shapes us, all the stuff behind the scenes,

...