The reference to corn originates in its role as one of the commodity crops that has turned North American agriculture into a blitzkrieg of chemical fertilizers, pesticides, industrial machinery and soil-eroding monocultures.

Only a small percentage of corn is consumed directly. Most is eaten in the form of chicken, pork, beef, eggs, milk and more.

Take those ubiquitous Chicken McNuggets. Not only are the chickens corn-fed, there's corn in the additives, the starches and the oils.

Snack foods, soft drinks — they're made from corn.

"We eat something like 56 pounds of high-fructose corn-syrup sweetener every year," Pollan told interviewer Blair Golson of Truthdig.com. "When you're drinking that soda, you're really drinking quite a bit of corn."

The story of corn is one of many Pollan tells in this book, a personal journey based on massive scholarship. It's a natural follow-up to his acclaimed 2001 book, The Botany of Desire, in which he proposed that plants are far from being passive participants in co-evolution.

We have so many choices because we're able to eat just about anything, writes Pollan, who also teaches journalism at the University of California at Berkeley. Yet we have become strangers to the things we eat.

No wonder so many North Americans, overfed yet undernourished, have such dysfunctional relationships with food.

"What I try to do in this book," he writes, "is approach the dinner question as a naturalist might, using the long lenses of ecology and anthropology, as well as the shorter, more intimate lens of personal experience."

A curious observer in the feedlot, on the grasslands and, finally, on a hunt for wild boar, he offers trenchant commentary and at-times exquisite prose. There are dozens of sentences and paragraphs that are worth a second read.

Corn seems a benign force, just a crop that covers hundreds of thousands of acres of farm fields — until you think back to the result of Ireland's monoculture in the 19th century (the potato blight that caused a million deaths by starvation) and until Pollan begins to investigate the use of corn feed for cattle through the short life of a young steer he bought and followed in an award-winning New York Times Magazine story.

After six months in the fields with its mother, the steer was sent to the feedlot to be fattened in record time, on corn.

Trouble is, cattle are ruminants, meant to eat grass. Corn effectively ruins their health, so they're filled with antibiotics that harm both eaten and eater.

We are pawns, Pollan argues, of agribusiness, of those huge conglomerates happy to offer sweet treats and otherwise empty calories.

He then investigates large-scale organic farming, which, he discovers, has been modelled on industrial agribusiness. This is "supermarket pastoral."

He raises questions about the meaning of "free-range" when animals are housed in huge sheds, and about the logic of using vast amounts of fossil-fuel energy to transport organic lettuce and eggs. He asks: Isn't "industrial organic" a contradiction in terms?

The most benevolent of the meals he consumes is based on grass. "Sustainably raised meat is ecologically a very positive thing for the environment, for the grasslands," he writes.

"Without animals on farms, you'd need artificial fertilizer because you wouldn't have manure to compost. So I think truly sustainable agriculture depends on animals in relation to plants."

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Other half of the article coming soon.