By the time Michael Pollan's "The Omnivore's Dilemma" first appeared in 2006, any American consumer with a crumb of curiosity about his or her food had already heard the sirens.

But the Berkeley professor's book, which explores the history and practices behind four meals, honed decades of low-level alarm about the American food system to a sharp edge. Cleaving through the clutter of competing claims and corporate spin, "The Omnivore's Dilemma," The News' November Book Club selection, changed the way millions of Americans think about dinner.

These days, Pollan's points find masses of supporters from coast to coast, as the local food movement gains activists and sensitized consumers. His main themes seem less controversial with each passing year:

The Omnivore's Dilemma: A Natural History of Four Meals

By Michael Pollan

Penguin Press; 464 pages, $10

The American factory food system is putting out more food than ever, but its bottom-line motives and lack of aggressive supervision can make people sick.

The organic alternatives in our supermarkets may not deliver on the implied claim that they are produced with healthier, more sustainable agricultural methods.

Since most people don't care where their food comes from, it's difficult to marshal opposition to bad agricultural practices. Despite all the well-meaning preaching from Pollan and company, most people don't have the energy to do anything about their food except eat it.

With "The Omnivore's Dilemma," Pollan encourages people to think back from the dollop of ground beef on a Styrofoam tray in the supermarket cooler.

One of Pollan's most significant contributions to the discussion is his focus on the role of oil and corn in our daily diets. The supermarket shelves in the United States are filled with products that rely on petroleum products such as pesticides and fertilizers to grow, and more petroleum burned by the engines that bring them to market.

That plastic tray the beef is on, the wrap around it? Those, too.

An astounding number rely on corn, whose vast government subsidies made it the dominant foodstuff on the American landscape. That's why it's used to fatten cattle, though nature designed them to run on grass. That's why corn products like high-fructose corn syrup are found in not only the bread in your sandwich, but the ketchup and baloney too.

It's not clear what the long-term effects of such a diet will be on the American population, because it's too recent a change for scientists to be certain. But some of the intermediate data is in; Pollan points to a study suggesting that one in three American children eat fast food daily. Could the epidemic of obesity facing the United States, especially among lower-earning households, be mere coincidence?

In his most hopeful chapters, Pollan explores a few small farms where food is raised differently. The amount of meat delivered by Joel Salatin's Polyface Farm, in Virginia's Shenandoah Valley, can only satisfy a statistically insignificant number of American consumers.

The lessons Pollan draws out of the farm are mighty. The sort of farming Salatin does may be harder and less forgiving of mistakes in certain ways, but it works for him. It proves that there is another way to feed Americans, Pollan suggests — a future of American food that every conscientious eater in the nation ought to hunger for, and help happen, one meal at a time.

As always, we are interested to hear your thoughts on "The Omnivore's Dilemma," as well as any suggestions you may have for future Book Club choices. E-mail the club at: bookclub@buffnews.com. Or, write to us at: The Buffalo News Book Club, P.O. Box 100, Buffalo, NY 14240.