Harvard Historian of Science Steven Shapin on the Nutrition Wars
Last month the US government issued a 571-page report suggesting it would be making significant changes to its dietary guidelines. Eggs are no longer a no-no. Caffeine consumption is encouraged to prevent Parkinson’s disease. The report comes at a time when new studies, and journalists including Gary Taubes, Nina Teicholz, and Aaron Carroll, have called into question the low-fat, high-carbohydrate diet promoted by the nutrition establishment for more than half a century.
Breakthrough is interested in the battle over dietary advice as an example of a “wicked problem” — a problem characterized by high levels of uncertainty and expert disagreement — and asked Harvard historian of science, Steven Shapin, to provide some historical and sociological context. Shapin is the author of numerous articles and books about the history diet and nutrition.
What is interesting about dietary advice to a historian of science?
I’m interested in the kinds of scientific knowledge that intersect with the texture of people’s everyday lives. What and how you eat is part of your identity — moral, ethnic, class, and so on. We eat three times a day, if we’re lucky. Eating has an instrumental dimension: you want to be healthy and live a long time. But it also has a moral dimension: gluttony used to be a sin, now obesity is a disease.
I’m also interested in the authority of modern expertise and its relationship to what people actually believe and do: diet and nutrition are areas in which the authority of modern expertise, and its influence on eating decisions, are problematic.
In 2002, the prominent New York University nutritionist Marion Nestle claimed there was “almost universal” expert consensus about the USDA Pyramid and that it would remain stable. Are claims of stable and near-universal nutrition expert consensus weakened by the changing science and recent US government nutrition report?
What we’re actually seeing is great instability in what the expertise says. One day dietary cholesterol is bad for you and the next day it is okay. I was raised to understand that if you ate fat you would become fat. When I was young, nobody talked about carbs being either bad or good or about the differences between types of carbohydrates. People didn’t then much mention salt, then it became bad, and as an ordinary eater I actually don’t know what the expert consensus now is, if there is one. So with great respect to Marion Nestle, it’s deeply problematic to say there is expert consensus, especially if you don’t know what she knows about who experts are.
Are we doomed to changing expertise and expert disagreement when it comes to diet and nutrition?
I’m a historian and I don’t predict the future, but historians will say that in an area like this, it’s not likely that any current state of affairs will persist forever. When it comes to present-day views of fat, of cholesterol, of fiber, of sodium, etc., it’s only prudent to expect change. The historian knows that views of food and eating have always been subject to change, and the historian is hard-pressed to see why such change should cease.
Is there a paradox here? On the one hand, we continue to look to experts for advice on diet and nutrition; on the other, we ignore their advice. A 2007 article in the Journal of Nutrition found as few as three to four percent of Americans actually follow the official dietary guidelines.
We read about the changing expert views on diet and nutrition, but we don’t lose faith in our view that there really is such a thing as dietary and nutritional expertise. We just play Ping-Pong with it. Somebody says, “I read this Harvard study,” and then someone else says, “I read something different.”
At the same time, the books that sell in the largest volume tend not to be the books by academic experts. People buy — or used to buy books — by Atkins and South Beach Diet author Agatston, and not so much books by Harvard nutritionist Walter Willett and Nestle. Recognizing this state of affairs is not, by the way, to applaud it. This is surely a problem for Nestle and Willett, but it’s also a problem for all of us because it’s a sign that we haven’t got a real consensus about what or whom to believe.
Is this a problem with expertise and science generally or is it specific to diet and nutrition?
One of the ways people get a sense of whether something is or is not a science is whether it is consensual and stable over time. Think of mathematical statements like 2+2=4 and how we encounter such things in school texts. But whether cholesterol is bad for you is not quite like 2+2=4.
We hear different things about cholesterol, at different times, in different settings, and from different sources. As a result, experts in fields like nutrition and sociology do not find it as easy to control their subject matter in the same way as do experts in physics or mathematics.
Is the problem that the nutrition guidelines are trying to be universal but our bodies and behaviors are so different?
The search for greater and greater universality may be important to dominant images of what science is, but we want to know about our particular bodies and not just about human bodies in general. What should I eat tonight? What should I be concerned about? What should I not worry about? People like Atkins found a way of weaving together the individuality of the anecdotes related in his books with a dose of science-sounding stuff, for example, claims about ketosis.
You note how long humans have said, in one form or another, “you are what you eat.” Do we still believe that?
Yes, but it means something different now than it once did. It used to refer to the food qualities and now it refers to food constituents. In past cultures, it was understood that food has qualities which may become your qualities. To be a beefeater was to be English. You eat beef and you become stolid, brave as a bull. Now we think not about the qualities as much as about the constituents — the stuff in the food, the chemicals. We may — still — think that cholesterol in your food puts cholesterol in your body.
You note that changes in what we think is bad and good for us often goes along with how we decide what is and isn’t a pollutant.
We’ve seen seismic historical shifts in what counts as dangerous and what counts as healthy. My grandmother said you have to eat a peck of dirt before you die, and we trade stories about traditional rules for how long food could stay on the kitchen floor before it became unsuitable for eating. This was not advice grounded in microbiology; it was part of a culture’s common-sense traditions.
[Nuclear physicist Edward] Teller would say a little radiation is good for you and is natural, whereas those of us who lived through paranoid decades of the Cold War often came to believe that all radiation was human-made and all radiation was bad for you. Anthropologists like the late Mary Douglas rightly reminded us that our sense of risk, danger, and pollution was central to our cultural life and also that it varied between cultures and over time.
Is it fair to say that foodie culture is a reaction against the modern view of food as ingredients and chemicals?
Absolutely. The diet Pollan commends amounts to a critique of capitalistic agribusiness and of many aspects of modernity, as does the Slow Food Movement of Carlo Petrini. One thing that Pollan does in his “eaters’ manifesto” is to rehearse the history of how nutritional knowledge became scientific — about how we came to think of food as an assemblage of chemicals—macronutrients and micronutrients, which we ought to consume in the right amounts and combinations. For Pollan, it’s a history of how we went wrong.
Where Nestle has a PhD in molecular biology, and her focus is in having the government recommend the proper quantities of different food constituents, Pollan likes to be seen as codifying and endorsing grandmotherly wisdom. For Nestle it’s things like “calories in, calories out” and “eat less refined foods,” whereas Pollan doesn’t like the language of chemical constituents and wants us to think of eating as a matter of prudence and balance and moderation.
Aren’t Pollan and Nestle simply offering different justifications for the same diet?
To some extent, yes. But while Pollan’s discomfort with “nutritionism” means that he tends to avoid the language of chemical constituents, it’s a discipline that he finds hard to stick with consistently. In his book, In Defense of Food, he can’t resist citing findings about the relationship between omega-3 and omega-6 fatty acids in grass-fed beef — and that’s just the sort of “nutritionist” vocabulary he elsewhere disapproves.
So even Pollan can’t escape nutritionism?
All of us now live in a culture saturated with scientific expertise about the constituents in our food—and so does he. Some writers might reject many aspects of that way of thinking about food, but it’s next to impossible not to absorb its claims.
Is what you’re describing an increasingly heterogeneity in diets and advice, with less regard to universal moral strictures?
Just look at the [San Francisco] Bay Area. You have, on the one hand, Soylent, the extreme representation of the view of diet as precisely compounded quantities of stuff the body needs for fuel and for repair. It’s a materialized representation of food as stuff that makes the body and makes the body run. It promotes efficiency and it provides an adequate supply of constituents at the lowest cost.
But you also have in the Bay Area incredibly innovative molecular gastronomy, with foams, gels, sous vide machines, and foods that nobody ever imagined before, and that derive from new science and new technology. And then you have Michael Pollan and Alice Waters searching for the perfect carrot at the farmer’s market.
You note that fat used to be a sign of wealth and today is a sign of poverty, and that they reversed after everybody — or at least most people — had enough to eat. The rich needed to distinguish themselves. Is foodie culture similarly a class distinction?
Absolutely. My wife is English and when she says that her maternal grandfather took three sugars in his strong tea she is telling you what kind of person he was. And when she herself takes very weak Earl Grey tea with no sugar, she is telling you who she is. The English use tea and its varieties to make fine social distinctions, and there are similar instances in other cultures.
In that sense is the ostensibly anti-modern foodie culture an engine of innovation in the modern food economy?
Our distinctions are more finely textured today because we deal with brands, and brands are in the business of distinction. Starbucks was once high-brow coffee, and now it’s less so. Modern hipsters now want to get their coffee from a non-franchise source. In coffee, as in many other things, the fashionistas require the unique, the indigenous, and the local. In one direction, the food industry is about franchising and extending brands, like Shake Shack and its recent IPO, it also goes in the other direction, toward the innovation of authenticity.
Do we focus so much on nutrition that we lose sight of the other reasons we eat?
Exactly. The great essayist Montaigne said as much in the late sixteenth century. The physician who cuts you off from this and from that, Montaigne said, performs the useful function of preparing you for death by making life not worth living. That’s a voice hard to hear in our society because it’s often assumed that everyone wants to live forever, at almost any cost. But food performs other functions that don’t have to do with health and longevity. Like my meal tonight, which will be braised short ribs and a nice bottle of Italian red.
Mashed potatoes and beets — will that be okay? But in thinking about what to cook for tonight I didn’t actually think about cholesterol or salt or fiber. I thought about what my wife and I might like to eat. So I could truthfully say that in deciding what to eat tonight, I did not consider dietary expertise, but, now that you mention it, I’ll probably cut some of the fat off the short ribs. My contradictions!