A natural historian is somebody who looks at something in terms of its relationship to the rest of the natural world. You look at things ecologically. When you see a cow on a feedlot, you don't just see a cow; you see a cow that is eating certain food. You follow that food and that food takes you back to a corn field.

What an extraordinary achievement for a civilization: to have developed the one diet that reliably makes its people sick!

When you go to the grocery store, you find that the cheapest calories are the ones that are going to make you the fattest - the added sugars and fats in processed foods.

Imagine for a moment if we once again knew, strictly as a matter of course, these few unremarkable things: What it is we're eating. Where it came from. How it found its way to our table. And what, in a true accounting, it really cost.

We're always projecting our moral categories on things. I think that's inevitable. But capitalism places no particular value on morality. Morality in the market is enforced by contract and regulation and law, because morality is understood to be in conflict with the motive force of greed and accumulation.

The food system is a very complex beast. There are people who are going to get their food at Wal-Mart or at Safeway; they're not going to the farmers' market. Those people need choices too.

I get letters from classes all the time. Say it's assigned in someone's 8th grade class, and the teacher asks everyone to write a letter to me about their impressions and what they learned. So, it's incredibly gratifying to hear.