[Book Notes] 10 insights: The Omnivore’s dilemma

Michael Pollan: “When you can eat just about anything nature has to offer, deciding what you should eat will inevitably stir anxiety, especially when some of the potential foods on offer are liable to sicken or kill you.”

This dilemma is the focus of Michael Pollan’s book The Omnivore’s Dilemma (book available here). The book provides a lot of detail on how our food consumption has changed in the last few decades and the impact it is having on us, our health, landscape, the environment and the animals. He talks about the motivation for different stakeholders in the supply chain – farmers, government, feedlots, consumer good companies, retailers – and how these incentives have led to an over reliance on corn. My notes from this book are as follows:


Agriculture can be viewed as a strategy used by plants/animals to domesticate humans vs. the other way round

We insist on speaking of the “invention” of agriculture as if it were our idea. However, it makes just as much sense to regard agriculture as a brilliant (if unconscious) evolutionary strategy on the part of the plants and animals to get us to advance their interests.

By evolving certain traits we happen to regard as desirable, these species got themselves noticed by the one mammal in a position not only to spread their genes around the world, but to remake vast swaths of that world in the image of the plants’ preferred habitat. No other group of species gained more from its association with humans than Zea mays (corn), today the world’s most important cereal crop.

Evolution of corn

There are some forty-five thousand items in the average American supermarket and more than a quarter of them now contain corn. This goes for nonfood items as well (e.g. toothpaste, matches…)



Corn helped in remaking the American landscape. Increase in yield led to farmers planting more of it. This was further catalyzed by demand for corn from central feedlots and the low human input needed for growing corn

It was the tractor, after all, that put the horses out of work, and with the horses went the oats fields and some of the pasture. But corn was the crop that put cash in the farmer’s pocket, so as corn yields began to soar at midcentury, the temptation was to give the miracle crop more and more land. Of course, every other farmer in America was thinking the same way, with the inevitable result that the price of corn declined.

Yield growth of corn

One might think falling corn prices would lead farmers to plant less of it, but the economics and psychology of agriculture are such that exactly the opposite happened. Beginning in the fifties and sixties, the flood tide of cheap corn made it profitable to fatten cattle on feedlots instead of on grass, and to raise chickens in giant factories rather than in farmyards.

Farmers couldn’t compete with the factory-farmed animals their own cheap corn had helped spawn, so the chickens and cattle disappeared from the farm, and with them pastures and hay fields and fences. In their place the farmers planted more of the one crop they could grow more of than anything else: corn. And whenever the price of corn slipped they planted a little more of it, to cover expenses and stay even.

By the 1980s the diversified family farm was history and corn was king. Now it proceeded to push out the people. The radically simplified farm of corn and soybeans doesn’t require nearly as much human labor as the old diversified farm. So the farms got bigger, and eventually the people, whom the steadily falling price of corn could no longer support anyway, went elsewhere, ceding the field to the monstrous grass.



The chemical fertilizer industry is the product of the government’s effort to convert its war machine to peacetime purposes

After world war 2, the government had found itself with a tremendous surplus of ammonium nitrate, the principal ingredient in the making of explosives. Ammonium nitrate also happens to be an excellent source of nitrogen for plants. Serious thought was given to spraying America’s forests with the surplus chemical, to help out the timber industry.  Ultimately the government decided to use this excess as a chemical fertilizer. Hybrid corn turned out to be the greatest beneficiary of this conversion. Hybrid corn is the greediest of plants, consuming more fertilizer than any other crop.



Two of every five humans on earth today would not be alive if not for Fritz Haber’s invention

Before 1909, all the usable nitrogen on earth had at one time been fixed by soil bacteria living on the roots of leguminous plants (such as peas) or, less commonly, by the shock of electrical lightning, which can break nitrogen bonds in the air, releasing a light rain of fertility. Therefore, the sheer amount of life earth could support was limited by the amount of nitrogen that bacteria and lightning could fix. This changed with the discovery of the Haber-Bosch process for fixing nitrogen.

World population supported by synthetic nitrogen fertilizers

When humankind acquired the power to fix nitrogen, the basis of soil fertility shifted from a total reliance on the energy of the sun to a new reliance on fossil fuel. The Haber-Bosch process works by combining nitrogen and hydrogen gases under immense heat and pressure in the presence of a catalyst. The heat and pressure are supplied by prodigious amounts of electricity, and the hydrogen is supplied by oil, coal, or, most commonly today, natural gas — fossil fuels.

True, these fossil fuels were at one time billions of years ago created by the sun, but they are not renewable in the same way that the fertility created by a legume nourished by sunlight is. Com adapted brilliantly to the new industrial regime, consuming prodigious quantities of fossil fuel energy and turning out ever more prodigious quantities of food energy. More than half of all the synthetic nitrogen made today is applied to corn, whose hybrid strains can make better use of it than any other plant.



The ninety-nine cent price of a fast-food hamburger simply doesn’t take account of that meal’s true cost — to soil, oil, public health, the public purse, etc., costs which are never charged directly to the consumer but, indirectly and invisibly, to the taxpayer (in the form of subsidies), the health care system (in the form of food-borne illnesses and obesity) , and the environment (in the form of pollution), not to mention the welfare of the workers in the feedlot and the slaughterhouse and the welfare of the animals themselves.

When you add together the natural gas in the fertilizer to the fossil fuels it takes to make the pesticides, drive the tractors, and harvest, dry, and transport the corn, you find that every bushel of industrial corn requires the equivalent of between a quarter and a third of a gallon of oil to grow it — or around fifty gallons of oil per acre of corn. (Some estimates are much higher.) 

As long as fossil fuel energy is so cheap and available, it makes good economic sense to produce corn this way. The old way of growing corn — using fertility drawn from the sun — may have been the biological equivalent of a free lunch, but the service was much slower and the portions were much skimpier. In the factory time is money, and yield is everything.

How many calories your dollars can buy


The demand for food isn’t elastic; people don’t eat more just because food is cheap

For as long as people have been farming, fat years have posed almost as stiff a challenge as lean, since crop surpluses collapse prices and bankrupt farmers who will be needed again when the inevitable lean years return. When it comes to food, nature can make a mockery of the classical economics of supply and demand — nature in the form of good or bad weather, of course, but also the nature of the human body, which can consume only so much food no matter how plentiful the supply.

Quote from a farmer: “The free market has never worked in agriculture and it never will. The economics of a family farm are very different than a firm’s: When prices fall, the firm can lay off people, idle factories, and make fewer widgets. Eventually the market finds a new balance between supply and demand.

But the demand for food isn’t elastic; people don’t eat more just because food is cheap. And laying off farmers doesn’t help to reduce supply. You can fire me, but you can’t fire my land, because some other farmer who needs more cash flow or thinks he’s more efficient  than I am will come in and farm it. Even if I go out of business this land will keep producing corn.” 

Corn has been exempted from the usual rules of nature and economics, both of which have rough mechanisms to check any such wild, uncontrolled proliferation. In nature, the population of a species explodes until it exhausts its supply of food; then it crashes. In the market, an oversupply of a commodity depresses prices until either the surplus is consumed or it no longer makes sense to produce any more of it. In corn’s case, humans have labored mightily to free it from either constraint, even if that means going broke growing it, and consuming it just as fast as we possibly can.



Food industries/CAFO looks at an animal as the best machine to convert field corn into meat

As animals moved from farms to CAFO — Concentrated Animal Feeding Operation, Corn itself profited from the urbanization of livestock twice. As the animals left the farm, more of the farm was left for corn, which rapidly colonized the paddocks and pastures and even the barnyards that had once been the animals’ territory. The animals left because the farmers simply couldn’t compete with the CAFOs. Corn profited again as the factory farms expanded, absorbing increasing amounts of its surplus. Corn found its way into the diet of animals that never used to eat very much of it (like cattle) or any corn at all, like the farmed salmon now being bred to tolerate grain.

Concentration of animal farms/ feedlots

Cows raised on grass simply take longer to reach slaughter weight than cows raised on a richer diet, and for half a century now the industry has devoted itself to shortening a beef animal’s allotted span on earth. What gets a steer from 80 to 1,100 pounds in fourteen months is tremendous quantities of corn, protein and fat supplements, and an arsenal of new drugs. Calories are calories, and corn is the cheapest, most convenient source of calories on the market. 

The conditions in CAFOs are dismal. For e.g. in the past, cows in CAFOs were fed cow parts and the industrialists thought this to be a sensible thing to do. Rendered bovine meat and bonemeal represented the cheapest, most convenient way of satisfying a cow’s protein requirement (never mind these animals were herbivores by evolution). The Food and Drug Administration (FDA) banned the practice in 1997 as scientists figured out that this practice was spreading bovine spongiform encephalopathy (BSE), more commonly known as mad cow disease.

Bloat is perhaps the most serious thing that can go wrong with a ruminant on corn. The fermentation in the rumen produces copious amounts of gas, which is normally expelled by belching during rumination. But when the diet contains too much starch and too little roughage, rumination all but stops, and a layer of foamy slime forms in the rumen that can trap the gas. The rumen inflates like a balloon until it presses against the animal’s lungs.

A concentrated diet of corn can also give a cow acidosis. Unlike our own highly acid stomachs, the normal pH of a rumen is neutral. Corn renders it acidic, causing a kind of bovine heartburn that in some cases can kill the animal, but usually just makes him sick.

What keeps a feedlot animal healthy — or healthy enough — are antibiotics. Most of the microbes that reside in the gut of a cow and find their way into our food get killed off by the strong acids in our stomachs, since they evolved to live in the neutral pH environment of the rumen. But the rumen of a corn-fed feedlot steer is nearly as acidic as our own stomachs, and in this new, man-made environment new acid-resistant strains of E. coli have evolved.

Poor conditions in a CAFO

Poor conditions in a CAFO

One way of looking at a cow in a CAFO – the feedlot way, the industrial way – was as a most impressive machine for turning field corn into cuts of beef. Every day between now and his slaughter in six months, a cow will convert thirty-two pounds of feed into four pounds of gain — new muscle, fat, and bone. Compared to other food animals, cattle are terribly inefficient: The ratio of feed to flesh in chicken, the most efficient animal by this measure, is two pounds of corn to one of meat, which is why chicken costs less than beef.



The human desire for sweetness surpasses even our desire for intoxication, the cleverest thing to do with a bushel of corn is to refine it into thirty- three pounds of high-fructose corn syrup

By the 1970s the process of refining corn into fructose had been perfected, and high-fructose corn syrup — which is a blend of 55 percent fructose and 45 percent glucose that tastes exactly as sweet as sucrose — came onto the market. Today, it is the most valuable food product refined from corn.

Yet the potential boon of falling raw material prices — which should allow you to sell a lot more of your product at a lower price — can’t be realized in the case of food because of the special nature of your consumer, who can eat only so much food, no matter how cheap it gets. (Food industry executives used to call this the problem of the “fixed stomach”; economists speak of “inelastic demand.”)

Nature has cursed the companies working the middle of the food chain with a recipe for falling rates of profits. The growth of the American food industry will always bump up against this troublesome biological fact: Try as we might, each of us can eat only about fifteen hundred pounds of food a year. Unlike many other products — CDs, say, or shoes — there’s a natural limit to how much food we can each consume without exploding. What this means for the food industry is that its natural rate of growth is somewhere around 1 percent per year — 1% being the annual growth rate of the American population. The problem is that won’t tolerate such an anemic rate of growth.

This leaves companies like General Mills and McDonald’s with two options if they hope to grow faster than the population: (1) figure out how to get people to spend more money for the same three-quarters of a ton of food, or (2) entice them to actually eat more than that.

The two strategies are not mutually exclusive, of course, and the food industry energetically pursues them both at the same time. Which is good news indeed for the hero of our story, for it happens that turning cheap corn into complex food systems is an excellent way to achieve both goals. The more complex your food system, the more you can practice “substitutionism” without altering the taste or appearance of the product.

So if the price of hydrogenated fat or lecithin derived from corn spikes one day, you simply switch to fat or lecithin from soy, and the consumer will never know the difference. (This is why ingredient labels says things like “Contains one or more of the following: corn, soybean, or sunflower oil”).

Growth in artificial sweetener

Today there are hundreds of things a processor can do with corn: They can use it to make everything from chicken nuggets and Big Macs to emulsifiers and nutraceuticals. Yet since the human desire for sweetness surpasses even our desire for intoxication, the cleverest thing to do with a bushel of corn is to refine it into thirty- three pounds of high-fructose corn syrup. That at least is what we’re doing with about 530 million bushels of the annual corn harvest — turning it into 17.5 billion pounds of high- fructose corn syrup.

Considering that the human animal did not taste this particular food until 1980, for HFCS to have become the leading source of sweetness in our diet stands as a notable achievement on the part of the corn-refining industry.



Researchers have found that people (and animals) presented with large portions will eat up to 30 percent more than they would otherwise

By 1984, Coca-Cola and Pepsi had switched over entirely from sugar to high-fructose corn syrup. Why? Because HFCS was a few cents cheaper than sugar (thanks in part to tariffs on imported sugarcane secured by the corn refiners) and consumers didn’t seem to notice the substitution.

Coca-Cola and Pepsi did not simply cut the price of a bottle of cola. That would only have hurt profit margins, for how many people are going to buy a second soda just because it cost a few cents less? The companies had a much better idea: They would supersize their sodas. Since a soft drink’s main raw material — corn sweetener — was now so cheap, why not get people to pay just a few pennies more for a substantially bigger bottle? Drop the price per ounce, but sell a lot more ounces.

So began the transformation of the svelte eight-ounce Coke bottle into the  chubby twenty-ouncer dispensed by most soda machines today. As the story is told in John Love’s official history of McDonald’s, Wallerstein tried everything he could think of to goose up sales — two-for-one deals, matinee specials — but found he simply could not induce customers to buy more than one soda and one bag of popcorn.

He thought he knew why: Going for seconds makes people feel piggish. Wallerstein discovered that people would spring for more popcorn and soda — a lot more — as long as it came in a single gigantic serving. Thus was born the two-quart bucket of popcorn, the sixty-four-ounce Big Gulp, and, in time, the Big Mac and the jumbo fries.

Increasing portion size in America

One might think that people would stop eating and drinking these gargantuan portions as soon as they felt full, but it turns out hunger doesn’t work that way. Researchers have found that people (and animals) presented with large portions will eat up to 30 percent more than they would otherwise. Human appetite, it turns out, is surprisingly elastic, which makes excellent evolutionary sense: It behooved our hunter-gatherer ancestors to feast whenever the opportunity presented itself, allowing them to build up reserves of fat against future famine. Obesity researchers call this trait the “thrifty gene.”



If our concern is for the health of nature — rather than, say, the internal consistency of our moral code or the condition of our souls — then eating animals may sometimes be the most ethical thing to do

Predation is deeply woven into the fabric of nature, and that fabric would quickly unravel if it somehow ended, if humans somehow managed “to do something about it.” From the point of view of the individual prey animal predation is a horror, but from the point of view of the group — and of its gene pool — it is indispensable. So whose point of view shall we favor?

Animal rights’ exclusive concern with the individual might make sense given its roots in a culture of liberal individualism, but how much sense does it make in nature? Is the individual animal the proper focus of our moral concern when we are trying to save an endangered species or restore a habitat?

If America was suddenly to adopt a strictly vegetarian diet, it isn’t at all clear that the total number of animals killed each year would necessarily decline, since to feed everyone animal pasture and rangeland would have to give way to more intensively cultivated row crops. If our goal is to kill as few animals as possible people should probably try to eat the largest possible animal that can live on the least cultivated land: grass-finished steaks for everyone.

Emissions from various food products

The vegan Utopia would also condemn people in many parts of the country to importing all their food from distant places. In New England, for example, the hilliness of the land and rockiness of the soil has dictated an agriculture based on grass and animals since the time of the Puritans. The world is full of places where the best, if not the only, way to obtain food from the land is by grazing (and hunting) animals on it — especially ruminants, which alone can transform grass  into protein.

To give up eating animals is to give up on these places as human habitat, unless of course we are willing to make complete our dependence on a highly industrialized national food chain. If our concern is for the health of nature — rather than, say, the internal consistency of our moral code or the condition of our souls — then eating animals may sometimes be the most ethical thing to do.



These days 19 percent of American meals are eaten in the car. The car has cup holders, front seat and rear, and, except for the salad, all the food (which we could have ordered, paid for, and picked up without opening the car door) can be readily eaten with one hand. Indeed, this is the genius of the chicken nugget: It liberated chicken from the fork and plate, making it as convenient, waste-free, and automobile-friendly as the pre-condimented hamburger. No doubt the food scientists at McDonald’s headquarters are right now hard at work on the one-handed salad.


A sweet tooth represents an excellent adaptation for an omnivore whose big brain demands a tremendous amount of glucose (the only type of energy the brain can use) , or at least it once did, when sources of sugar were few and far between. (The adult human brain accounts for 2 percent of our body weight but consumes 18 percent of our energy, all of which must come from a carbohydrate). Our sense of taste’s second big bias predisposes us against bitter flavors, which is how many of the defensive toxins produced by plants happen to taste. Pregnant women are particularly sensitive to bitter tastes, probably an adaptation to protect the developing fetus against even the mild plant toxins found in foods like broccoli.

Humans also learned to overcome plant defenses by cooking or otherwise processing foods to remove their bitter toxins. The dangers of eating raw fish, for example, are minimized by consuming it with wasabi, a potent antimicrobial. Similarly, the strong spices characteristic of many cuisines in the tropics, where food is quick to spoil, have antibacterial properties.


Corn enjoyed certain botanical advantages that would allow it to thrive. No other plant could produce quite as much food quite as fast on a given patch of New World ground as this Indian corn. The plant — whose prodigious genetic variability allows it to adapt rapidly to new conditions — made itself at home in virtually every microclimate in North America. Corn won over the wheat people because of its versatility, prized especially in new settlements far from civilization.

Corn could be brewed into beer or distilled into whiskey; for a time it was the only source of alcohol on the frontier. No part of the big grass went to waste: The husks could be woven into rugs and twine; the leaves and stalks made good silage for livestock; the shelled cobs were  burned for heat and stacked by the privy as a rough substitute for toilet paper (Hence the American slang term “corn hole.”)


We are processed corn, walking. During photosynthesis, most plants create compounds that have three carbon atoms. However, corn (along with a small handful of other species) make compounds that have four: hence “C4,” the botanical nickname for this gifted group of plants.

The C4 trick represents an important economy for a plant, giving it an advantage, especially in areas where water is scarce and temperatures high. In order to gather carbon atoms from the air, a plant has to open its stomata, the microscopic orifices in the leaves through which plants both take in and exhaust gases. Every time a stoma opens to admit carbon dioxide precious molecules of water escape. It’s as though every time you opened your mouth to eat you lost a quantity of blood. Ideally, you would open your mouth as seldom as possible, ingesting as much food as you could with every bite. This is essentially what a C4 plant does. By recruiting extra atoms of carbon during each instance of photosynthesis, the corn plant is able to limit its loss of water and “fix” — that is, take from the atmosphere and link in a useful molecule — significantly more carbon than other plants.

When a C4 plant goes scavenging for its four-packs of carbon, it takes in more carbon 13 than ordinary — C3 — plants, which exhibit a marked preference for the more common carbon 12. The higher the ratio of carbon 1 3 to carbon 12 in a person’s flesh, the more corn has been in his diet — or in the diet of the animals he or she ate. One would expect to find a comparatively high proportion of carbon 1 3 in the flesh of people whose staple food of choice is corn — Mexicans, most famously. Americans eat much more wheat than corn — 114 pounds of wheat flour per person per year, compared to 11 pounds of corn flour. But carbon 13 doesn’t lie, and researchers who have compared the isotopes in the flesh or hair of North Americans to those in the same tissues of Mexicans report that it is now we in the North who are the true people of corn.

“When you look at the isotope ratios,” Todd Dawson, a Berkeley biologist who’s done this sort of re- search, told me, “we North Americans look like corn chips with legs.” Compared to us, Mexicans today consume a far more varied carbon diet: the animals they eat still eat grass (until recently, Mexicans regarded feeding corn to livestock as a sacrilege); much of their protein comes from legumes; and they still sweeten their beverages with cane sugar.