I think using waste oils as fuel makes sense. We do waste a huge amount of vegetable oil in this country and using that as a fuel source strikes me as fine.

Don't eat any foods you've ever seen advertised on television.

People who snack sometimes sometimes eat kind of thoughtlessly and end up eating a lot more. But in principle, it's a really good idea if you can exert the kind of discipline needed.

One surprise is how deeply the food system is implicated in climate change. I don't think that has really been on people's radar until very recently. 25 to 33 percent of climate change gases can be traced to the food system. I was also surprised that those diseases that we take for granted as what will kill us - heart disease, cancer, diabetes - were virtually unknown 150 years ago, before we began eating this way.

Corn is the hero of its own story, and though we humans played a crucial supporting role in its rise to world domination, it would be wrong to suggest we have been calling the shots, or acting always in our own best interests. Indeed, there is every reason to believe that corn has succeeded in domesticating us.

We are not only what we eat, but how we eat, too.

Not everyone can afford to eat well in America, which is a literal shame, but most of us can: Americans spend less than 10 percent of their income on food, less than the citizens of any other nation.