This happens at three different stages. One is on the farm, because we use synthetic nitrogen fertilizer, which is made from natural gas and a great deal of electricity.

Then we take commodity crops, such as corn and soybeans and wheat, and we process them intensively, adding another seven calories of fossil-fuel energy for every one calorie of food. It's a very intensive process to take the corn and turn it into the high-fructose corn syrup, or take the corn and turn it into the chicken, and the chicken into the Chicken McNugget. As we move further away from eating food to eating highly processed, complicated food products -- as we move from yogurt to Go-GURT -- it takes more energy, and more energy in the packaging. We're putting a lot of time into redesigning our whole food supply so we can eat in the car. Nineteen percent of meals [and snacks in the U.S.] are eaten in the car right now.

And then we drive [the food] around the country, if not fly it around the world. You can get your organic asparagus from Argentina, you can get your grass-fed beef from New Zealand.

So given that our most serious environmental problem is global warming, I'd have to say the most serious problem with the food system is its contribution to global warming.

While it has always been evident that modern agribusiness is a very energy-intensive industry, I still find it interesting that Pollan considers this the most worrisome aspect of the food production system. More worrisome than the powerful but wasteful subsidies? More worrisome than the obesity problem? It would be easy enough to convince me, but in fact our food production system has so many problems that it's hard to know where to start. Yet, Pollan may be understating the energy issue: not only is our food production system contributing to global warming, but his comments also underscore how vulnerable we will be once the access to cheap oil is restricted.

The interview also tackles topics such as why large-scale organic farming is moving ever further from the sustainable ideal, the lure of microwaveable "convenience foods", and the challenge of convincing people that understanding where their food comes from is a really important issue.

Also, Pollan-junkies might be interested in his blog at the New York Times.