In The Omnivore's Dilemma: A Natural History of Four Meals, food writer and UC-Berkeley professor Michael Pollan examines three American food supply chains: the industrial, which encompasses factory farming and supermarkets; the organic, which includes family farms and other small-scale producers; and what he calls "the hunter-gatherer" food supply chain, which we experience when scavenging for ourselves.

Pollan explains in satisfying detail how American food production, once sun-based, became fossil-fuel based: Instead of using the sun to grow grass to feed cows, we now use fossil fuels to process corn into feed for pigs and cows—and to process corn into feed for humans. (Corn syrup shows up in everything from ice cream to loaves of bread; other corn derivatives are used as binders, emulsifiers, and sweeteners, typically for canned, frozen, and packaged goods.) As a result, Pollan argues, food is much cheaper and more plentiful than it used to be, but our health, the environment, and animals have suffered.

Pollan's book becomes less satisfying, however, when he sets out to answer the question: How should a responsible person eat in the modern world? He persuasively points out that the obvious solutions—buying organic, shopping at Whole Foods, eating exclusively "free-range" chickens—are insufficient. Organic farming has simply become another branch of the industrial food-distribution system (sure enough, after Pollan's book appeared, Wal-Mart announced that it would sell organic food). And though we feel good about eating "free-range" chickens—and are willing to pay more for them—many of those birds don't fare much better than their peers: They often receive only a few inches of additional space in factory farms and then a few weeks' time to step outside through a tiny door—and most chickens stay inside, having learned a fear of the unknown.

In the book's final chapter, Pollan presents his own model for responsible eating, chronicling his memorable attempt to cook and consume a meal that he had grown and killed himself. He gathers his own mushrooms and then hunts down, cooks, and serves a wild boar. The episode is riveting, even if Pollan does give himself a leg up on our nomadic forbears, using a high-powered rifle to kill the boar and GPS to locate the mushrooms and find his way back.

Pollan argues that the costs and benefits of a meal should be as transparent as possible so that eaters are aware of the impact of their food decisions on the environment; he claims that his pig hunt roughly approximates this standard. But Pollan's hunt is far from transparent. For one, the reader suspects that Pollan created the meal, in part, so he could create a best-selling book. A true accounting of the pig hunt should tally up the petroleum used to ship The Omnivore's Dilemma around the country and send Pollan on a speaker's tour. (We could add the energy consumed by Slate's servers, which of course make it possible to post this piece.) More important, Pollan neglects another cost of his "perfect" meal: Our author's time is gone forever. There are plenty of "cheap" ways to procure food if we do not measure our time and trouble as relevant costs.

The problems with Pollan's "self-financed" meal reflect the major shortcoming of the book: He focuses on what is before his eyes but neglects the macro perspective of the economist. He wants to make the costs of various foods transparent, but this is an unattainable ideal, given the interconnectedness of markets. Often the best ways to solve environmental problems are invisible and not available to the consumer in the supermarket aisle. We can tax or regulate offending activities, such as fertilizer runoff or the bad treatment of animals. But we cannot always tell how much environmental evil any given foodstuff contains.

Pollan makes much of the energy costs incurred by the long food supply chains of American grocery stores. It may look like we are eating Chilean grapes, he argues, but in fact, once we consider transportation costs, we are guzzling petroleum. Economics offers a clearer view of what is going on. We do need to save energy, but it is difficult for a central planner (or for that matter a food commentator) to identify what is waste, relative to the costs of eliminating it. We should rely on higher market prices, if need be with the assistance of taxes, to increase conservation. If fuel becomes more expensive, we'll likely adopt peak-load energy pricing, and drivers may scrap their SUVs for hybrids. But we probably won't plant grapes in our backyards. While we must conserve energy, we cut back where it makes the most sense; grape-shipping is not the place to start. Global trade does involve transportation costs, but it also puts food production where it is cheapest, again saving energy by economizing on costs of labor, irrigation, and fertilization, relative to the alternatives.

Pollan also argues against free trade in agriculture, on the grounds that the economics will bankrupt family farms and destabilize the market; Pollan fears centralization and the industrial mode of production. He does not note, however, that New Zealand has moved to free agricultural markets—virtually no subsidies or tariffs—and its farms, including family farms, have flourished. Nor should we forget that farm protectionism, as practiced in the EU and elsewhere, costs billions and damages economic development in poorer countries that might otherwise ship foodstuffs to the wealthier West.

Although Pollan is knowledgeable and his argument sophisticated, he does not escape a fuzzy nostalgia for the preindustrial past. In Pollan's breakthrough book, his 1991 Second Nature: A Gardener's Education, he considers how man should relate to nature and puts forth a metaphor of man as gardener. Perhaps this construct, which encourages a small-scale and piecemeal view of our food world, explains where he goes wrong.

In Second Nature, Pollan rejects all-or-nothing approaches to the natural world. He argues that we should neither romanticize nature as an untouchable preserve, nor plunder it with abandon. Instead, he says, we should pursue an enlightened self-interest in our relationship with the environment, using it—responsibly and sustainably—to meet our needs. We need to restrain ourselves and thereby allow nature, and our species, to survive.

The ideas are powerful, but the garden is not a useful way to think about food markets. Pollan does not acknowledge how much his garden construct is historically specific. Early crop-growing, circa 5000 B.C. or even 1700 A.D., was no fun. The labor was backbreaking, and whether it rained, or when the frost came, was often a matter of life or death. And proper gardens—as a source of pleasure rather than survival—became widespread only with the appearance of capitalist wealth and leisure time, both results of man's dominion over nature. The English gardening tradition blossomed in the 18^th century, along with consumer society and a nascent Industrial Revolution.

In other words, the garden ideal is possible in some spheres only because it is rejected in so many others. It is the cultures of the scientists and engineers that have allowed gardens—and also a regular food supply—to flourish in the modern world.

So, let us not judge food markets by whichever costs we observe on a fact-finding trip. Society uses markets, prices, and formal accounting precisely because a narrative is as likely to mislead us about social costs as not. Markets may require tinkering, but to make that judgment, let us put down that hoe and pick up a price-theory textbook.