But even a cursory analysis of the study’s methods makes you wonder why anyone would take such a finding seriously, let alone order a Quarter Pounder With Cheese to celebrate it, as many newspaper readers no doubt promptly went out and did. Even the beginner student of nutritionism will immediately spot several flaws: the focus was on “fat,” rather than on any particular food, like meat or dairy. So women could comply simply by switching to lower-fat animal products. Also, no distinctions were made between types of fat: women getting their allowable portion of fat from olive oil or fish were lumped together with woman getting their fat from low-fat cheese or chicken breasts or margarine. Why? Because when the study was designed 16 years ago, the whole notion of “good fats” was not yet on the scientific scope. Scientists study what scientists can see.
But perhaps the biggest flaw in this study, and other studies like it, is that we have no idea what these women were really eating because, like most people when asked about their diet, they lied about it. How do we know this? Deduction. Consider: When the study began, the average participant weighed in at 170 pounds and claimed to be eating 1,800 calories a day. It would take an unusual metabolism to maintain that weight on so little food. And it would take an even freakier metabolism to drop only one or two pounds after getting down to a diet of 1,400 to 1,500 calories a day — as the women on the “low-fat” regimen claimed to have done. Sorry, ladies, but I just don’t buy it.
In fact, nobody buys it. Even the scientists who conduct this sort of research conduct it in the knowledge that people lie about their food intake all the time. They even have scientific figures for the magnitude of the lie. Dietary trials like the Women’s Health Initiative rely on “food-frequency questionnaires,” and studies suggest that people on average eat between a fifth and a third more than they claim to on the questionnaires. How do the researchers know that? By comparing what people report on questionnaires with interviews about their dietary intake over the previous 24 hours, thought to be somewhat more reliable. In fact, the magnitude of the lie could be much greater, judging by the huge disparity between the total number of food calories produced every day for each American (3,900 calories) and the average number of those calories Americans own up to chomping: 2,000. (Waste accounts for some of the disparity, but nowhere near all of it.) All we really know about how much people actually eat is that the real number lies somewhere between those two figures.
To try to fill out the food-frequency questionnaire used by the Women’s Health Initiative, as I recently did, is to realize just how shaky the data on which such trials rely really are. The survey, which took about 45 minutes to complete, started off with some relatively easy questions: “Did you eat chicken or turkey during the last three months?” Having answered yes, I was then asked, “When you ate chicken or turkey, how often did you eat the skin?” But the survey soon became harder, as when it asked me to think back over the past three months to recall whether when I ate okra, squash or yams, they were fried, and if so, were they fried in stick margarine, tub margarine, butter, “shortening” (in which category they inexplicably lump together hydrogenated vegetable oil and lard), olive or canola oil or nonstick spray? I honestly didn’t remember, and in the case of any okra eaten in a restaurant, even a hypnotist could not get out of me what sort of fat it was fried in. In the meat section, the portion sizes specified haven’t been seen in America since the Hoover administration. If a four-ounce portion of steak is considered “medium,” was I really going to admit that the steak I enjoyed on an unrecallable number of occasions during the past three months was probably the equivalent of two or three (or, in the case of a steakhouse steak, no less than four) of these portions? I think not. In fact, most of the “medium serving sizes” to which I was asked to compare my own consumption made me feel piggish enough to want to shave a few ounces here, a few there. (I mean, I wasn’t under oath or anything, was I?)
This is the sort of data on which the largest questions of diet and health are being decided in America today.
THE ELEPHANT IN THE ROOM
In the end, the biggest, most ambitious and widely reported studies of diet and health leave more or less undisturbed the main features of the Western diet: lots of meat and processed foods, lots of added fat and sugar, lots of everything — except fruits, vegetables and whole grains. In keeping with the nutritionism paradigm and the limits of reductionist science, the researchers fiddle with single nutrients as best they can, but the populations they recruit and study are typical American eaters doing what typical American eaters do: trying to eat a little less of this nutrient, a little more of that, depending on the latest thinking. (One problem with the control groups in these studies is that they too are exposed to nutritional fads in the culture, so over time their eating habits come to more closely resemble the habits of the intervention group.) It should not surprise us that the findings of such research would be so equivocal and confusing.
But what about the elephant in the room — the Western diet? It might be useful, in the midst of our deepening confusion about nutrition, to review what we do know about diet and health. What we know is that people who eat the way we do in America today suffer much higher rates of cancer, heart disease, diabetes and obesity than people eating more traditional diets. (Four of the 10 leading killers in America are linked to diet.) Further, we know that simply by moving to America, people from nations with low rates of these “diseases of affluence” will quickly acquire them. Nutritionism by and large takes the Western diet as a given, seeking to moderate its most deleterious effects by isolating the bad nutrients in it — things like fat, sugar, salt — and encouraging the public and the food industry to limit them. But after several decades of nutrient-based health advice, rates of cancer and heart disease in the U.S. have declined only slightly (mortality from heart disease is down since the ’50s, but this is mainly because of improved treatment), and rates of obesity and diabetes have soared.
No one likes to admit that his or her best efforts at understanding and solving a problem have actually made the problem worse, but that’s exactly what has happened in the case of nutritionism. Scientists operating with the best of intentions, using the best tools at their disposal, have taught us to look at food in a way that has diminished our pleasure in eating it while doing little or nothing to improve our health. Perhaps what we need now is a broader, less reductive view of what food is, one that is at once more ecological and cultural. What would happen, for example, if we were to start thinking about food as less of a thing and more of a relationship?
In nature, that is of course precisely what eating has always been: relationships among species in what we call food chains, or webs, that reach all the way down to the soil. Species co-evolve with the other species they eat, and very often a relationship of interdependence develops: I’ll feed you if you spread around my genes. A gradual process of mutual adaptation transforms something like an apple or a squash into a nutritious and tasty food for a hungry animal. Over time and through trial and error, the plant becomes tastier (and often more conspicuous) in order to gratify the animal’s needs and desires, while the animal gradually acquires whatever digestive tools (enzymes, etc.) are needed to make optimal use of the plant. Similarly, cow’s milk did not start out as a nutritious food for humans; in fact, it made them sick until humans who lived around cows evolved the ability to digest lactose as adults. This development proved much to the advantage of both the milk drinkers and the cows.
“Health” is, among other things, the byproduct of being involved in these sorts of relationships in a food chain — involved in a great many of them, in the case of an omnivorous creature like us. Further, when the health of one link of the food chain is disturbed, it can affect all the creatures in it. When the soil is sick or in some way deficient, so will be the grasses that grow in that soil and the cattle that eat the grasses and the people who drink the milk. Or, as the English agronomist Sir Albert Howard put it in 1945 in “The Soil and Health” (a founding text of organic agriculture), we would do well to regard “the whole problem of health in soil, plant, animal and man as one great subject.” Our personal health is inextricably bound up with the health of the entire food web.
In many cases, long familiarity between foods and their eaters leads to elaborate systems of communications up and down the food chain, so that a creature’s senses come to recognize foods as suitable by taste and smell and color, and our bodies learn what to do with these foods after they pass the test of the senses, producing in anticipation the chemicals necessary to break them down. Health depends on knowing how to read these biological signals: this smells spoiled; this looks ripe; that’s one good-looking cow. This is easier to do when a creature has long experience of a food, and much harder when a food has been designed expressly to deceive its senses — with artificial flavors, say, or synthetic sweeteners.