Good science isn’t bad for our diet: a critique of Michael Pollan’s food politics

Good science isn’t bad for our diet: a critique of Michael Pollan’s food politics

Nutrition science gets a bad rap in Michael Pollan's bestselling books

No recent writings on food politics have been as influential as those of Michael Pollan, Knight Professor of Science and Environmental Journalism at UC Berkeley. Perhaps on account of Pollan’s uncanny ability to make anything from agricultural policy to moral philosophy seem exciting, his books The Omnivore’s Dilemma (2006) and In Defense of Food (2008), as well as his writings in The New York Times Magazine, have opened the eyes of millions of readers to the ills of the modern food system — everything from the feedlot steer sleeping in a pile of manure to the baleful influence of the food industry on our agricultural and public health policies. Too often, however, the same works vilify and otherwise misrepresent science, drawing from selective readings of sources and an overly simplistic view of scientific inquiry to attribute the poor health of modern society and the environment to shortcomings inherent in the scientific method.

In The Omnivore’s Dilemma, Pollan suggests that developments in the field of agricultural science have been detrimental to our “national health.” In particular, Pollan cites Baron Justus von Liebig’s 19th century discovery that plants need only nitrogen, phosphorous, and potassium to grow as a possible reason for our society’s poor nourishment. Leaning heavily on Sir Albert Howard’s An Agricultural Testament (1940), Pollan criticizes the practice of substituting these three nutrients for biologically-rich humus (the decomposing organic matter in topsoil), a practice rooted in what Howard called the “NPK mentality” after the symbols for those three nutrients:

To reduce such a vast biological complexity to NPK represented the scientific method at its reductionist worst. Complex qualities are reduced to simple quantities; biology gives way to chemistry. As Howard was not the first to point out, that method can only deal with one or two variables at a time. The problem is that once science has reduced a complex phenomenon to couple of variables, however important they may be, the natural tendency is to overlook everything else, to assume that what you can measure is all there is, or at least all that really matters. When we mistake what we can know for all there is to know, a healthy appreciation of one’s ignorance in the face of a mystery like soil fertility gives way to the hubris that we can treat nature as a machine.

Reading Pollan’s summary of An Agricultural Testament, one might easily be led to believe that Howard’s book was some kind of anti-science screed. However, although Howard devoted a full chapter to criticizing agricultural science as it was typically practiced in his day, criticism of the scientific method more broadly is nowhere to be found in the work.

To clarify this point, it’s worth recalling what is meant by that phrase, “the scientific method.” This refers to a very general method for gathering and organizing knowledge; it’s a sort of systematization of the trial-and-error process. The scientific method involves seeking the answer to a question by using observations to make a hypothesis, using the hypothesis to make a prediction which is then tested experimentally, and using the results to form a new hypothesis.

Author and professor Michael Pollan

Critically, the reduction of complex qualities to simple quantities or biology to chemistry isn’t an essential part of the scientific method. Howard recognized as much in An Agricultural Testament. In a chapter titled “Soil Fertility and National Health,” he proposed a set of experiments to answer the question, “How does the produce of an impoverished soil affect the men and women who have to consume it?” Howard further reaffirmed his belief in science in his conclusion, writing, “the investigator of the future will only differ from the farmer in the possession of an extra implement — science — and in the wider experience which travel confers.”

In spite of these words, Pollan writes, “Howard’s concept of organic agriculture is premodern, arguably even antiscientific: He’s telling us we don’t need to understand how humus works or what compost does in order to make good use of it.” Such a statement misrepresents Howard’s work and, as importantly, misrepresents what science is. After all, science does not mandate that we hand substances like humus and compost to a chemist for further analysis before we use them.

To Howard, the problem with conventional agriculture wasn’t that it was overly scientific but that it wasn’t. He wrote:

The policy of protecting crops from pests by means of sprays, powders, and so forth is unscientific and unsound as, even when successful, such procedure merely preserves the unfit and obscures the real problem — how to grow healthy crops.

Whereas Pollan believes that conventional agriculture is driven by “the scientific method at its reductionist worst,” Howard considered reductionism itself to be unscientific, a consequence of researchers focusing on the wrong problem. In fact, Howard blamed this reductionism not on science but on economics: “The need for reducing expenditure so that farming could yield a profit has brought every operation, including manuring and the treatment of disease, under examination in order to ascertain the cost and what profit, if any, results.” So is it business people, not scientists, who are really at fault here? Let’s leave that question to another post.

For now, we return to Pollan’s second major book on food politics, In Defense of Food, in which he takes on reductionism in nutritional science. He starts off innocently enough, assuring the reader that nutrition science can teach us important things, “at least when it avoids the pitfalls of reductionism and overconfidence.” Reductionism in this context refers to the ideology of “nutritionism,” the idea that foods can be reduced to their constituent nutrients.

It isn’t long before things take a turn for the worse, however, when Pollan suggests that this reductionism is an inevitable part of nutrition science:

Scientists study variables they can isolate; if they can’t isolate a variable, they won’t be able to tell whether its presence or absence is meaningful…So if you’re a nutrition scientist you do the only thing you can do, given the tools at your disposal: Break the [food] down into its component parts and study those one by one, even if that means ignoring subtle interactions and the fact that the whole may well be more than, or maybe just different from, the sum of its parts.

In spite of the aura of inevitability the Pollan imparts to reductionism in his writing, there’s no particular reason that nutrition scientists can’t study foods as a whole; indeed, they often do. Pollan himself notes (for example), “researchers have long believe that a diet containing lots of fruits and vegetables confers some protection against cancer.”

Senator George McGovern

To Pollan, the “supreme test” of the ideology of nutritionism was the low-fat campaign that gained traction in the late 1970’s and early 1980’s. The low-fat movement went mainstream after the 1977 publication of the Dietary Goals for the United States by Senator George McGovern’s Select Committee on Nutrition and Human Needs  and the 1982 publication of the National Academy of Sciences’ Diet, Nutrition, and Cancer. In Pollan’s view, the campaign represented nutritionism’s “most abject failure.” He explains, “Americans got really fat on their new low-fat diet — indeed, many date the current epidemic of obesity and diabetes to the late 1970s, when Americans began bingeing [sic] on carbohydrates, ostensibly as a way to avoid the evils of fat.”

Pollan quotes a 2001 critical review stating that “the low-fat campaign has been based on little scientific evidence.” Without bothering to explain how nutritionism might be discredited by the failure of a public health campaign that wasn’t supported by science, Pollan presents an alternative theory and its implications for the low-fat advice:

The theory is that refined carbohydrates interfere with insulin metabolism in ways that increase hunger and promote overeating and fat storage in the body…If this is true, then there is no escaping the conclusion that the dietary advice enshrined not only in the McGovern “Goals” but also in the National Academy of Sciences report, the dietary guidelines of the American Heart Association and the American Cancer Society and the U.S. food pyramid bears direct responsibility for creating the public health crisis that now confronts us.

This passage implies that the various dietary guidelines that supported the low-fat movement encouraged Americans to compensate for the reduction in calories from fat by eating more white flour and high-fructose corn syrup. However, McGovern’s Goals called for a substantial reduction in sugar consumption and an increase in consumption of carbohydrates from fruits, vegetables, and grains. Americans increased their sugar consumption and disregarded a recommended decrease in daily energy intake. Incredibly, on the basis of their having followed the recommendation to decrease the percentage of calories consumed in the form of fat, Pollan has declared the Goals not merely unhelpful but directly responsible for the current public health crisis. (This is, to say the least, a surprising departure from Pollan’s explanation of the same crisis in The Omnivore’s Dilemma: “When food is abundant and cheap, people will eat more of it and get fat.”)

Ultimately, the overarching rules at which Pollan arrives (“Eat food. Not too much. Mostly plants.”) may well lead a reader to a diet not far from the scientific mainstream. The work also includes some valuable warnings against the dangers of reductionism. Regrettably, though, as in The Omnivore’s Dilemma, Pollan presents an overstated case against science, and the result is an argument layered with contradiction and distortion. Supporters of food reform would do far better to follow Sir Albert Howard’s model and criticize science done badly but embrace good science as a vital part of a better food system.

Adam Merberg (@adammerberg) is a Ph.D. Candidate in Mathematics at UC Berkeley. He regularly critiques Michael Pollan’s work on his blog, Say What, Michael Pollan?.

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14 comments

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  3. richard mcmahan

    Understanding that Senator George McGovern submitted something other than what Pollan is critical of, what do you think went wrong to have such an effect? The “low fat” thing was very popular. Do you have a thought to share on why this apparent fallacy went on as long as it did?
    Thank you for your hard work, and your posts.

  4. B Channing Hillway, PhD

    Thanks for a fine article, Adam.

    First, it is important to recognize the excellent work Pollan has done in making a great many people more aware of the issues of agriculture and, especially, the industrialization of agriculture for profit. If he has made occasional missteps in failing to adequately understand and/or explain, and if he has shortchanged some in the process, that is certainly fruit for discussion. Nevertheless, Pollan’s contribution has been monumental and the academic community and learned critics may wish to address any disparities in the spirit of small corrections that are offered to strengthen Pollan’s work.

    Second, in response to Richard McMahan, coconut oil and lard are superior to hydrogenated vegetable oils, e.g., Crisco, that were introduced when industrial agriculture sought to convert waste material into a profitable substance. Coconut oil conveys a wealth of benefits. Lard is not wonderful, but it is healthier than Crisco since it is not hydrogenated. But coconut oil and lard were vilified and driven into the background. The anti-fat movement, decades later, which has been very harmful to the health of Americans, was developed from a single flawed study that the grain industry grabbed and celebrated as a new “truth,” and it has been discredited. There never was a credible body of research to support the anti-fat diet. The suggestion that, instead. people should be eating carbohydrates, which was a strategy by the grain industry to boost profits, has been a disaster, with an explosion in the incidence of diabetes at all ages and especially among school children, and increases heart and other diseases. The addition of high fructose corn syrup, found in an astounding number of processed and/or packaged foods, has made things far worse. Read Dr. Cordain’s, The Paleo Diet, for more evidence from how our ancestors ate foods based in a digestive system that additional evidence suggests dates back at least 1.8 million years — we got our digestive system before we got our bigger brains. Those ancestors simply did not eat grains unless they were starving. The fallacy that grains is a healthy replacement for fat has gone on as long is due to billions of dollars in advertising. So much of the “food-like substances,” as Pollan describes processed and packaged foods, are also cheaper and easier to consume. Cheetos are much quicker and easier than purchasing a large bag of organic carrots at Costco, removing only the damaged peeling, and then cutting into bite sized snacks. The salt and fat in Cheetos is seductive, they look and taste like fun, and they take up space in one’s daily nutrition that becomes a trash space where better nutrition is needed. The carrots are probably cheaper and much more nutritious, but people used to being seduced by Cheetos, chips and other salty stuff made with fats that are not recommended, will usually find the carrots bland. Once a great diet based on vegetable snacks is embraced, the Cheetos and chips begin to taste not very good, even irritating. The billions of dollars spent on seducing the public and keeping them grabbing for poor nutrition based on fat, sugar and salt has allowed the low fat myth to go. Granted the Cheetos are a form of cheating, but they are the result of daily eating that is not based on fresh organic pastured dairy butter, organic extra virgin olive oil, organic extra virgin coconut oil, and omega-3 fatty acids (your brain is made of them) from small, northern, wild caught fish where short life span means very little mercury has had time to accumulate. Round out the diet with pastured beef, free range fowl, and wild caught, small northern fish, with a cornucopia of organic fruits and veggies, and a healthy diet is restored.

    There is so much to learn and, then, to turn into a daily, operational, nutritional plan, it is a study in itself. I am now telling people that 70, which is my present age, is the new 50. I have my fingers crossed and nothing would compel to return to a diet of manufactured trash created by the corporatocracy of industrialized agriculture. My health is too valuable to me.

  5. No. 534

    I was poking around Michael Pollan’s site when I stumbled across this blatant example of his misrepresentation of science, perhaps better stated as some sort of fear or hatred of science. He’s adding new food rules to a release of the similarly titled book, and has a preview of some new additions:

    Michael Pollan Counts Down His Favorite New Rules
    http://michaelpollan.com/books/food-rules-illustrated-edition/michael-pollan-counts-down-his-favorite-new-rules/

    #7. Enjoy Drinks That Have Been Caffeinated by Nature, Not Food Science

    Coffee and tea can make us happy, alert, and more energetic, which might help explain why scientists have worked so hard to find something wrong with them. At one time or another, these traditional caffeinated beverages have been linked to heart disease, cancer, hypertension, and bone loss, but so far coffee and tea have been exonerated on every count. And in fact the antioxidants in coffee and tea (as well as in chocolate, which also contains caffeine) may do us some good. Too much caffeine can make people jittery and anxious, however, and the jury is still out on the new generation of caffeinated energy drinks. So at least for now, you’re probably better off getting your caffeine, in moderation, from a plant rather than a factory.

    Say what?!

    “Scientists have worked so hard to find something wrong” with coffee and tea? That’s a grand accusation. I don’t doubt that scientists have focused on potential health risks of coffee and tea, but this is likely from a similar cultural inquiry that many health conscious people have due to the stimulating, addictive qualities of these beverages. People from your general health food consumers to religious groups like Seventh-Day Adventists and Mormons tend to eschew coffee and (black) tea since the long term effects of caffeine are suspect.

    So while I’m sure that at least a few studies may have found some correlations with caffeine consumption and negative health outcomes, Pollan sites this as science’s bad influence on food, as if all scientists had an agenda to discredit these beverages. But then he goes right ahead and lauds how coffee and tea have been exonerated, but failed to mention by whom. Food scientists maybe? He wouldn’t even have this language of beneficial antioxidants if it weren’t for food scientists. What “jury” is he talking about when contemplating whether caffeinated energy drinks are harmful or not? Food scientists!

  6. RD

    A lot of these arguments hold some weight, but I can’t help but feel they seem nit-picky. The point Pollan is making in discussing the scientific method is what the need to name chemicals in food has done to the general public’s knowledge… are you arguing that humanity doesn’t tend to reduce complex phenomena into a few measurable variables? This book is speaking to the general public, many of whom don’t realize how simplified nutrition has become and are willing to put their future health in the hands of a multivitamin.
    I just feel that the point he’s making that we should remain mindful of nutrition’s complexity is step that leads him to the point that we should be consuming whole food sources of nutrition that our bodies are meant to digest. This message is SO important and he’s reaching people with it. Does the fact that you don’t view the scientific method the same way that he does make his point less valid? There’s a lot of criticism here for his tactics and not much addressing of the take-home information–which is what really matters.

  7. RD

    These’s opinions are far superior to apathy… I just think they seem a little like misguided time and energy…

  8. Adam Merberg

    Thanks for all the comments, and my apologies for the delay in the response.

    @Richard,
    I think the key point here is that the lipid hypothesis hasn’t been discredited to the extent that Pollan would have you believe. It’s evolved somewhat in that researchers now believe that the ratios of different kinds of fats is more important than the total amount of fat.

    @Dr. Hillway and RD,
    I don’t agree that what I’ve written about here amounts to “small corrections” or “nit-picking.” How we define science is fundamental to any discussion of the role of science in our society. In that regard, I don’t think I’m nit-picking here any more than I’d be nit-picking by raising concern about a crack in the foundation of a house. Yes, the crack might be only a small part of the house, but that doesn’t mean the whole house won’t come tumbling down.

    What I think is most disturbing about the issues I’ve written about here is the way in which science takes the blame for the problems of the political atmosphere. In his denunciation of nutritionism, Pollan tells us of the cattle ranchers’ role in having the advice to reduce meat consumption stricken from the Dietary Goals, of the food industry’s funding of research to prove the healthfulness of their products, and of the food processors’ rush to provide us with “low-fat pork, low-fat Snackwell’s, and all the low-fat pasta and high-fructose (yet low-fat!) corn syrup we could consume.” If, however, the problem lies with listening to science, the message is that all of these things are inescapable consequences of paying attention to scientists, and that there is no point in working for a government that listens to scientists instead of lobbyists, for science untainted by corporate interests, or for the repeal of the agricultural subsidies that make cheap high-fructose corn syrup possible. I think that the political implications of that proposition are very dangerous.

    Furthermore, I think Pollan plays to a general distrust of science and scientists which is all too common these days. The same sort of sentiment underlies climate denialism and the anti-evolution movement, and those of us who care about science would do well to correct it regardless of the source. If Pollan’s problem is really with reductionism, there’s no need to confuse things by pointing fingers at the scientific method.

    The last point I would make is that I think it is particularly problematic that (as in the instances cited above) Pollan presents his sources in a way that distorts their meaning. Many of the claims in his written work would require retractions if published in a scholarly journal. That doesn’t mean that his work does not have a place in the public discourse, but it suggests that they are primarily valuable as works of punditry or activism rather than as a source of accurate information. It seems to me that both Dr. Hillway and RD implicitly accept this point in defending Pollan on the basis of his getting a message out to people. Given that Pollan is often labeled an expert on food issues and that his books are sometimes assigned in college level courses, it seems important to bring this to the discussion.

    @No. 534,
    The bit you object to–”Scientists have worked so hard to find something wrong” with coffee and tea–seems like it’s probably at least a bit tongue-in-cheek. I do think, however, that it’s pretty unhelpful with the public’s existing distrust and misunderstanding of science. It’s probably more helpful with selling books, though.

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