This interview excerpt originally appeared in Political Awakenings: Conversations with History, published by The New Press.

Harry Kreisler (HK): In understanding food and agribusiness, politics is very important.

Michael Pollan (MP): We’re not aware of it, but food, like everything, is political. It is the biggest industry in the country; it’s the most essential thing. We’ve had the luxury of not having to think about it for the last thirty years, thanks to Earl Butz and having all this cheap food around. But you know, if we as a society have to live without gasoline, which is unimaginable, we will figure out how to do it. We did it for millions of years. We’ve never lived without food. Food is really essential, and when you have anything that’s essential, there is enormous political and economic forces that contend about how it will be organized.

In the last thirty years, we have had this kind of agriculture industrial complex, which by some measures has worked quite well. It’s kept the price of food low; it’s kept the food industry healthy; it’s given us a lot of power overseas–we’re big food exporters–but what we’re getting in touch with, I think, is that the by-products of that system, or the unintended consequences and costs, are catching up–every thing from obesity to diabetes.

Because that was a system that specifically encouraged the consumption of cheap corn sweeteners, high fructose corn syrup, hydrogenated oils from soy, processed foods of all kinds, a lot of cheap meat. So, there’s been a public health impact that’s dramatic. That is what’s bankrupting the health care system: the fact that half of us suffer from chronic diseases linked to the diet.

There are $250 billion a year in costs tied to that. So, that’s one set of problems.

The other set, of course, is environmental. The food system contributes more greenhouse gases than anything else, any other industry, and that happens at every level. It happens at the field, the way we fertilize crops, in the amount of energy that goes to produce that fertilizer, the way we use machinery on the farms, the way we process the food, the amount of animals, and the methane we release. It’s about a third of greenhouse gases [that] come from the food system, and transporting the food all around the world, not to mention the agricultural pollution. Feed lots are the biggest source of pollution we have.

I mean, it’s quite an accomplishment that you can go to a restaurant, eat a fast food meal, a big chunk of meat, French fries, large soda, for less than the minimum wage. In the history of humankind, that’s quite an achievement, but it’s come at a very high cost, and that cost, I think, is what we’re getting in touch with right now.

HK: You’ve suggested that part of the problem is that industrial capitalism and agro-capitalism essentially take a discovery and then find the best way to make the most money as soon as possible ….

MP: With incomplete information.

HK: Right.

MP: Well, genetically modified crops is another great example. We figured out something about genes, and we understand some connection between a gene, a protein, and a trait, and so we figured out a couple crops where we could introduce new genes from other crops. It works, but we overlook a whole lot of complexity, which we just dismiss as static. Why is it that when we introduce this gene, 90 percent of the time you get a freak plant?

Well, we don’t really know; it has something to do with gene expression; it has something to do with junk DNA. Look, reductive science is very powerful, but it’s always important to understand that you’re missing some of the complexity. When you apply that reductive science you can get into trouble because you’re mistaking what you know for all there is to know. So, there’s a lack of humility involved, and there is a tendency to apply these things long before we know what’s working and what’s not working.

HK: A key turning point here is the Haber-Bosch process, which you’ve written about. Talk a little about that because it is a major turning point in seeing synthetic fertilizer as the be-all and end-all of every thing.

MP: The great crisis of 1900 was there’s not enough nitrogen to feed everybody. Before then, all the nitrogen that was used in agriculture came from bacteria in the soil fixing it. That was proving to be inadequate; crops were failing. The Haber-Bosch process is basically the fixing of nitrogen, synthetic nitrogen, and it was a great invention; by some estimates 40 percent of the people on earth are here because of that process.

However, it’s a great example of a powerful technology that’s had a lot of negative effects. Synthetic nitrogen, when it oxidizes in the soil, becomes nitrous oxide, which is a very potent greenhouse gas. Nitrogen fertilizer became so cheap and is used so profligately that it runs down the Mississippi River and into the Gulf of Mexico, where it has created this dead zone. And over time we have found that using too much synthetic nitrogen ruins the structure of the soil; it becomes too salty and basically nothing will grow. And you have the declining yield curve that we’ve seen all through the green revolution countries because of too much nitrogen in the fertilizer.