Wednesday, March 17, 2010

Eat food. Not too much. Mostly plants.

An article worth reading and rereading:

New York Times, January 28, 2007
Unhappy Meals

By MICHAEL POLLAN
Eat food. Not too much. Mostly plants.

That, more or less, is the short answer to the supposedly incredibly
complicated and confusing question of what we humans should eat in
order to be maximally healthy. I hate to give away the game right here
at the beginning of a long essay, and I confess that I'm tempted to
complicate matters in the interest of keeping things going for a few
thousand more words. I'll try to resist but will go ahead and add a
couple more details to flesh out the advice. Like: A little meat won't
kill you, though it's better approached as a side dish than as a main.
And you're much better off eating whole fresh foods than processed
food products. That's what I mean by the recommendation to eat "food."
Once, food was all you could eat, but today there are lots of other
edible foodlike substances in the supermarket. These novel products of
food science often come in packages festooned with health claims,
which brings me to a related rule of thumb: if you're concerned about
your health, you should probably avoid food products that make health
claims. Why? Because a health claim on a food product is a good
indication that it's not really food, and food is what you want to
eat.

Uh-oh. Things are suddenly sounding a little more complicated, aren't
they? Sorry. But that's how it goes as soon as you try to get to the
bottom of the whole vexing question of food and health. Before long, a
dense cloud bank of confusion moves in. Sooner or later, everything
solid you thought you knew about the links between diet and health
gets blown away in the gust of the latest study.

Last winter came the news that a low-fat diet, long believed to
protect against breast cancer, may do no such thing — this from the
monumental, federally financed Women's Health Initiative, which has
also found no link between a low-fat diet and rates of coronary
disease. The year before we learned that dietary fiber might not, as
we had been confidently told, help prevent colon cancer. Just last
fall two prestigious studies on omega-3 fats published at the same
time presented us with strikingly different conclusions. While the
Institute of Medicine stated that "it is uncertain how much these
omega-3s contribute to improving health" (and they might do the
opposite if you get them from mercury-contaminated fish), a Harvard
study declared that simply by eating a couple of servings of fish each
week (or by downing enough fish oil), you could cut your risk of dying
from a heart attack by more than a third — a stunningly hopeful piece
of news. It's no wonder that omega-3 fatty acids are poised to become
the oat bran of 2007, as food scientists micro-encapsulate fish oil
and algae oil and blast them into such formerly all-terrestrial foods
as bread and tortillas, milk and yogurt and cheese, all of which will
soon, you can be sure, sprout fishy new health claims. (Remember the
rule?)

By now you're probably registering the cognitive dissonance of the
supermarket shopper or science-section reader, as well as some
nostalgia for the simplicity and solidity of the first few sentences
of this essay. Which I'm still prepared to defend against the shifting
winds of nutritional science and food-industry marketing. But before I
do that, it might be useful to figure out how we arrived at our
present state of nutritional confusion and anxiety.

The story of how the most basic questions about what to eat ever got
so complicated reveals a great deal about the institutional
imperatives of the food industry, nutritional science and — ahem —
journalism, three parties that stand to gain much from widespread
confusion surrounding what is, after all, the most elemental question
an omnivore confronts. Humans deciding what to eat without expert help
— something they have been doing with notable success since coming
down out of the trees — is seriously unprofitable if you're a food
company, distinctly risky if you're a nutritionist and just plain
boring if you're a newspaper editor or journalist. (Or, for that
matter, an eater. Who wants to hear, yet again, "Eat more fruits and
vegetables"?) And so, like a large gray fog, a great Conspiracy of
Confusion has gathered around the simplest questions of nutrition —
much to the advantage of everybody involved. Except perhaps the
ostensible beneficiary of all this nutritional expertise and advice:
us, and our health and happiness as eaters.

FROM FOODS TO NUTRIENTS

It was in the 1980s that food began disappearing from the American
supermarket, gradually to be replaced by "nutrients," which are not
the same thing. Where once the familiar names of recognizable
comestibles — things like eggs or breakfast cereal or cookies —
claimed pride of place on the brightly colored packages crowding the
aisles, now new terms like "fiber" and "cholesterol" and "saturated
fat" rose to large-type prominence. More important than mere foods,
the presence or absence of these invisible substances was now
generally believed to confer health benefits on their eaters. Foods by
comparison were coarse, old-fashioned and decidedly unscientific
things — who could say what was in them, really? But nutrients — those
chemical compounds and minerals in foods that nutritionists have
deemed important to health — gleamed with the promise of scientific
certainty; eat more of the right ones, fewer of the wrong, and you
would live longer and avoid chronic diseases.

Nutrients themselves had been around, as a concept, since the early
19th century, when the English doctor and chemist William Prout
identified what came to be called the "macronutrients": protein, fat
and carbohydrates. It was thought that that was pretty much all there
was going on in food, until doctors noticed that an adequate supply of
the big three did not necessarily keep people nourished. At the end of
the 19th century, British doctors were puzzled by the fact that
Chinese laborers in the Malay states were dying of a disease called
beriberi, which didn't seem to afflict Tamils or native Malays. The
mystery was solved when someone pointed out that the Chinese ate
"polished," or white, rice, while the others ate rice that hadn't been
mechanically milled. A few years later, Casimir Funk, a Polish
chemist, discovered the "essential nutrient" in rice husks that
protected against beriberi and called it a "vitamine," the first
micronutrient. Vitamins brought a kind of glamour to the science of
nutrition, and though certain sectors of the population began to eat
by its expert lights, it really wasn't until late in the 20th century
that nutrients managed to push food aside in the popular imagination
of what it means to eat.

No single event marked the shift from eating food to eating nutrients,
though in retrospect a little-noticed political dust-up in Washington
in 1977 seems to have helped propel American food culture down this
dimly lighted path. Responding to an alarming increase in chronic
diseases linked to diet — including heart disease, cancer and diabetes
— a Senate Select Committee on Nutrition, headed by George McGovern,
held hearings on the problem and prepared what by all rights should
have been an uncontroversial document called "Dietary Goals for the
United States." The committee learned that while rates of coronary
heart disease had soared in America since World War II, other cultures
that consumed traditional diets based largely on plants had strikingly
low rates of chronic disease. Epidemiologists also had observed that
in America during the war years, when meat and dairy products were
strictly rationed, the rate of heart disease temporarily plummeted.

Naïvely putting two and two together, the committee drafted a
straightforward set of dietary guidelines calling on Americans to cut
down on red meat and dairy products. Within weeks a firestorm,
emanating from the red-meat and dairy industries, engulfed the
committee, and Senator McGovern (who had a great many cattle ranchers
among his South Dakota constituents) was forced to beat a retreat. The
committee's recommendations were hastily rewritten. Plain talk about
food — the committee had advised Americans to actually "reduce
consumption of meat" — was replaced by artful compromise: "Choose
meats, poultry and fish that will reduce saturated-fat intake."

A subtle change in emphasis, you might say, but a world of difference
just the same. First, the stark message to "eat less" of a particular
food has been deep-sixed; don't look for it ever again in any official
U.S. dietary pronouncement. Second, notice how distinctions between
entities as different as fish and beef and chicken have collapsed;
those three venerable foods, each representing an entirely different
taxonomic class, are now lumped together as delivery systems for a
single nutrient. Notice too how the new language exonerates the foods
themselves; now the culprit is an obscure, invisible, tasteless — and
politically unconnected — substance that may or may not lurk in them
called "saturated fat."

The linguistic capitulation did nothing to rescue McGovern from his
blunder; the very next election, in 1980, the beef lobby helped
rusticate the three-term senator, sending an unmistakable warning to
anyone who would challenge the American diet, and in particular the
big chunk of animal protein sitting in the middle of its plate.
Henceforth, government dietary guidelines would shun plain talk about
whole foods, each of which has its trade association on Capitol Hill,
and would instead arrive clothed in scientific euphemism and speaking
of nutrients, entities that few Americans really understood but that
lack powerful lobbies in Washington. This was precisely the tack taken
by the National Academy of Sciences when it issued its landmark report
on diet and cancer in 1982. Organized nutrient by nutrient in a way
guaranteed to offend no food group, it codified the official new
dietary language. Industry and media followed suit, and terms like
polyunsaturated, cholesterol, monounsaturated, carbohydrate, fiber,
polyphenols, amino acids and carotenes soon colonized much of the
cultural space previously occupied by the tangible substance formerly
known as food. The Age of Nutritionism had arrived.

THE RISE OF NUTRITIONISM

The first thing to understand about nutritionism — I first encountered
the term in the work of an Australian sociologist of science named
Gyorgy Scrinis — is that it is not quite the same as nutrition. As the
"ism" suggests, it is not a scientific subject but an ideology.
Ideologies are ways of organizing large swaths of life and experience
under a set of shared but unexamined assumptions. This quality makes
an ideology particularly hard to see, at least while it's exerting its
hold on your culture. A reigning ideology is a little like the
weather, all pervasive and virtually inescapable. Still, we can try.

In the case of nutritionism, the widely shared but unexamined
assumption is that the key to understanding food is indeed the
nutrient. From this basic premise flow several others. Since
nutrients, as compared with foods, are invisible and therefore
slightly mysterious, it falls to the scientists (and to the
journalists through whom the scientists speak) to explain the hidden
reality of foods to us. To enter a world in which you dine on unseen
nutrients, you need lots of expert help.

But expert help to do what, exactly? This brings us to another
unexamined assumption: that the whole point of eating is to maintain
and promote bodily health. Hippocrates's famous injunction to "let
food be thy medicine" is ritually invoked to support this notion. I'll
leave the premise alone for now, except to point out that it is not
shared by all cultures and that the experience of these other cultures
suggests that, paradoxically, viewing food as being about things other
than bodily health — like pleasure, say, or socializing — makes people
no less healthy; indeed, there's some reason to believe that it may
make them more healthy. This is what we usually have in mind when we
speak of the "French paradox" — the fact that a population that eats
all sorts of unhealthful nutrients is in many ways healthier than we
Americans are. So there is at least a question as to whether
nutritionism is actually any good for you.

Another potentially serious weakness of nutritionist ideology is that
it has trouble discerning qualitative distinctions between foods. So
fish, beef and chicken through the nutritionists' lens become mere
delivery systems for varying quantities of fats and proteins and
whatever other nutrients are on their scope. Similarly, any
qualitative distinctions between processed foods and whole foods
disappear when your focus is on quantifying the nutrients they contain
(or, more precisely, the known nutrients).

This is a great boon for manufacturers of processed food, and it helps
explain why they have been so happy to get with the nutritionism
program. In the years following McGovern's capitulation and the 1982
National Academy report, the food industry set about re-engineering
thousands of popular food products to contain more of the nutrients
that science and government had deemed the good ones and less of the
bad, and by the late '80s a golden era of food science was upon us.
The Year of Eating Oat Bran — also known as 1988 — served as a kind of
coming-out party for the food scientists, who succeeded in getting the
material into nearly every processed food sold in America. Oat bran's
moment on the dietary stage didn't last long, but the pattern had been
established, and every few years since then a new oat bran has taken
its turn under the marketing lights. (Here comes omega-3!)

By comparison, the typical real food has more trouble competing under
the rules of nutritionism, if only because something like a banana or
an avocado can't easily change its nutritional stripes (though rest
assured the genetic engineers are hard at work on the problem). So
far, at least, you can't put oat bran in a banana. So depending on the
reigning nutritional orthodoxy, the avocado might be either a high-fat
food to be avoided (Old Think) or a food high in monounsaturated fat
to be embraced (New Think). The fate of each whole food rises and
falls with every change in the nutritional weather, while the
processed foods are simply reformulated. That's why when the Atkins
mania hit the food industry, bread and pasta were given a quick
redesign (dialing back the carbs; boosting the protein), while the
poor unreconstructed potatoes and carrots were left out in the cold.

Of course it's also a lot easier to slap a health claim on a box of
sugary cereal than on a potato or carrot, with the perverse result
that the most healthful foods in the supermarket sit there quietly in
the produce section, silent as stroke victims, while a few aisles
over, the Cocoa Puffs and Lucky Charms are screaming about their
newfound whole-grain goodness.

EAT RIGHT, GET FATTER

So nutritionism is good for business. But is it good for us? You might
think that a national fixation on nutrients would lead to measurable
improvements in the public health. But for that to happen, the
underlying nutritional science, as well as the policy recommendations
(and the journalism) based on that science, would have to be sound.
This has seldom been the case.

Consider what happened immediately after the 1977 "Dietary Goals" —
McGovern's masterpiece of politico-nutritionist compromise. In the
wake of the panel's recommendation that we cut down on saturated fat,
a recommendation seconded by the 1982 National Academy report on
cancer, Americans did indeed change their diets, endeavoring for a
quarter-century to do what they had been told. Well, kind of. The
industrial food supply was promptly reformulated to reflect the
official advice, giving us low-fat pork, low-fat Snackwell's and all
the low-fat pasta and high-fructose (yet low-fat!) corn syrup we could
consume. Which turned out to be quite a lot. Oddly, America got really
fat on its new low-fat diet — indeed, many date the current obesity
and diabetes epidemic to the late 1970s, when Americans began binging
on carbohydrates, ostensibly as a way to avoid the evils of fat.

This story has been told before, notably in these pages ("What if It's
All Been a Big Fat Lie?" by Gary Taubes, July 7, 2002), but it's a
little more complicated than the official version suggests. In that
version, which inspired the most recent Atkins craze, we were told
that America got fat when, responding to bad scientific advice, it
shifted its diet from fats to carbs, suggesting that a re-evaluation
of the two nutrients is in order: fat doesn't make you fat; carbs do.
(Why this should have come as news is a mystery: as long as people
have been raising animals for food, they have fattened them on carbs.)

But there are a couple of problems with this revisionist picture.
First, while it is true that Americans post-1977 did begin binging on
carbs, and that fat as a percentage of total calories in the American
diet declined, we never did in fact cut down on our consumption of
fat. Meat consumption actually climbed. We just heaped a bunch more
carbs onto our plates, obscuring perhaps, but not replacing, the
expanding chunk of animal protein squatting in the center.

How did that happen? I would submit that the ideology of nutritionism
deserves as much of the blame as the carbohydrates themselves do —
that and human nature. By framing dietary advice in terms of good and
bad nutrients, and by burying the recommendation that we should eat
less of any particular food, it was easy for the take-home message of
the 1977 and 1982 dietary guidelines to be simplified as follows: Eat
more low-fat foods. And that is what we did. We're always happy to
receive a dispensation to eat more of something (with the possible
exception of oat bran), and one of the things nutritionism reliably
gives us is some such dispensation: low-fat cookies then, low-carb
beer now. It's hard to imagine the low-fat craze taking off as it did
if McGovern's original food-based recommendations had stood: eat fewer
meat and dairy products. For how do you get from that stark counsel to
the idea that another case of Snackwell's is just what the doctor
ordered?

BAD SCIENCE

But if nutritionism leads to a kind of false consciousness in the mind
of the eater, the ideology can just as easily mislead the scientist.
Most nutritional science involves studying one nutrient at a time, an
approach that even nutritionists who do it will tell you is deeply
flawed. "The problem with nutrient-by-nutrient nutrition science,"
points out Marion Nestle, the New York University nutritionist, "is
that it takes the nutrient out of the context of food, the food out of
the context of diet and the diet out of the context of lifestyle."

If nutritional scientists know this, why do they do it anyway? Because
a nutrient bias is built into the way science is done: scientists need
individual variables they can isolate. Yet even the simplest food is a
hopelessly complex thing to study, a virtual wilderness of chemical
compounds, many of which exist in complex and dynamic relation to one
another, and all of which together are in the process of changing from
one state to another. So if you're a nutritional scientist, you do the
only thing you can do, given the tools at your disposal: break the
thing down into its component parts and study those one by one, even
if that means ignoring complex interactions and contexts, as well as
the fact that the whole may be more than, or just different from, the
sum of its parts. This is what we mean by reductionist science.

Scientific reductionism is an undeniably powerful tool, but it can
mislead us too, especially when applied to something as complex as, on
the one side, a food, and on the other, a human eater. It encourages
us to take a mechanistic view of that transaction: put in this
nutrient; get out that physiological result. Yet people differ in
important ways. Some populations can metabolize sugars better than
others; depending on your evolutionary heritage, you may or may not be
able to digest the lactose in milk. The specific ecology of your
intestines helps determine how efficiently you digest what you eat, so
that the same input of 100 calories may yield more or less energy
depending on the proportion of Firmicutes and Bacteroidetes living in
your gut. There is nothing very machinelike about the human eater, and
so to think of food as simply fuel is wrong.

Also, people don't eat nutrients, they eat foods, and foods can behave
very differently than the nutrients they contain. Researchers have
long believed, based on epidemiological comparisons of different
populations, that a diet high in fruits and vegetables confers some
protection against cancer. So naturally they ask, What nutrients in
those plant foods are responsible for that effect? One hypothesis is
that the antioxidants in fresh produce — compounds like beta carotene,
lycopene, vitamin E, etc. — are the X factor. It makes good sense:
these molecules (which plants produce to protect themselves from the
highly reactive oxygen atoms produced in photosynthesis) vanquish the
free radicals in our bodies, which can damage DNA and initiate
cancers. At least that's how it seems to work in the test tube. Yet as
soon as you remove these useful molecules from the context of the
whole foods they're found in, as we've done in creating antioxidant
supplements, they don't work at all. Indeed, in the case of beta
carotene ingested as a supplement, scientists have discovered that it
actually increases the risk of certain cancers. Big oops.

What's going on here? We don't know. It could be the vagaries of human
digestion. Maybe the fiber (or some other component) in a carrot
protects the antioxidant molecules from destruction by stomach acids
early in the digestive process. Or it could be that we isolated the
wrong antioxidant. Beta is just one of a whole slew of carotenes found
in common vegetables; maybe we focused on the wrong one. Or maybe beta
carotene works as an antioxidant only in concert with some other plant
chemical or process; under other circumstances, it may behave as a
pro-oxidant.

Indeed, to look at the chemical composition of any common food plant
is to realize just how much complexity lurks within it. Here's a list
of just the antioxidants that have been identified in garden-variety
thyme:

4-Terpineol, alanine, anethole, apigenin, ascorbic acid, beta
carotene, caffeic acid, camphene, carvacrol, chlorogenic acid,
chrysoeriol, eriodictyol, eugenol, ferulic acid, gallic acid,
gamma-terpinene isochlorogenic acid, isoeugenol, isothymonin,
kaempferol, labiatic acid, lauric acid, linalyl acetate, luteolin,
methionine, myrcene, myristic acid, naringenin, oleanolic acid,
p-coumoric acid, p-hydroxy-benzoic acid, palmitic acid, rosmarinic
acid, selenium, tannin, thymol, tryptophan, ursolic acid, vanillic
acid.

This is what you're ingesting when you eat food flavored with thyme.
Some of these chemicals are broken down by your digestion, but others
are going on to do undetermined things to your body: turning some
gene's expression on or off, perhaps, or heading off a free radical
before it disturbs a strand of DNA deep in some cell. It would be
great to know how this all works, but in the meantime we can enjoy
thyme in the knowledge that it probably doesn't do any harm (since
people have been eating it forever) and that it may actually do some
good (since people have been eating it forever) and that even if it
does nothing, we like the way it tastes.

It's also important to remind ourselves that what reductive science
can manage to perceive well enough to isolate and study is subject to
change, and that we have a tendency to assume that what we can see is
all there is to see. When William Prout isolated the big three
macronutrients, scientists figured they now understood food and what
the body needs from it; when the vitamins were isolated a few decades
later, scientists thought, O.K., now we really understand food and
what the body needs to be healthy; today it's the polyphenols and
carotenoids that seem all-important. But who knows what the hell else
is going on deep in the soul of a carrot?

The good news is that, to the carrot eater, it doesn't matter. That's
the great thing about eating food as compared with nutrients: you
don't need to fathom a carrot's complexity to reap its benefits.

The case of the antioxidants points up the dangers in taking a
nutrient out of the context of food; as Nestle suggests, scientists
make a second, related error when they study the food out of the
context of the diet. We don't eat just one thing, and when we are
eating any one thing, we're not eating another. We also eat foods in
combinations and in orders that can affect how they're absorbed. Drink
coffee with your steak, and your body won't be able to fully absorb
the iron in the meat. The trace of limestone in the corn tortilla
unlocks essential amino acids in the corn that would otherwise remain
unavailable. Some of those compounds in that sprig of thyme may well
affect my digestion of the dish I add it to, helping to break down one
compound or possibly stimulate production of an enzyme to detoxify
another. We have barely begun to understand the relationships among
foods in a cuisine.

But we do understand some of the simplest relationships, like the
zero-sum relationship: that if you eat a lot of meat you're probably
not eating a lot of vegetables. This simple fact may explain why
populations that eat diets high in meat have higher rates of coronary
heart disease and cancer than those that don't. Yet nutritionism
encourages us to look elsewhere for the explanation: deep within the
meat itself, to the culpable nutrient, which scientists have long
assumed to be the saturated fat. So they are baffled when
large-population studies, like the Women's Health Initiative, fail to
find that reducing fat intake significantly reduces the incidence of
heart disease or cancer.

Of course thanks to the low-fat fad (inspired by the very same
reductionist fat hypothesis), it is entirely possible to reduce your
intake of saturated fat without significantly reducing your
consumption of animal protein: just drink the low-fat milk and order
the skinless chicken breast or the turkey bacon. So maybe the culprit
nutrient in meat and dairy is the animal protein itself, as some
researchers now hypothesize. (The Cornell nutritionist T. Colin
Campbell argues as much in his recent book, "The China Study.") Or, as
the Harvard epidemiologist Walter C. Willett suggests, it could be the
steroid hormones typically present in the milk and meat; these
hormones (which occur naturally in meat and milk but are often
augmented in industrial production) are known to promote certain
cancers.

But people worried about their health needn't wait for scientists to
settle this question before deciding that it might be wise to eat more
plants and less meat. This is of course precisely what the McGovern
committee was trying to tell us.

Nestle also cautions against taking the diet out of the context of the
lifestyle. The Mediterranean diet is widely believed to be one of the
most healthful ways to eat, yet much of what we know about it is based
on studies of people living on the island of Crete in the 1950s, who
in many respects lived lives very different from our own. Yes, they
ate lots of olive oil and little meat. But they also did more physical
labor. They fasted regularly. They ate a lot of wild greens — weeds.
And, perhaps most important, they consumed far fewer total calories
than we do. Similarly, much of what we know about the health benefits
of a vegetarian diet is based on studies of Seventh Day Adventists,
who muddy the nutritional picture by drinking absolutely no alcohol
and never smoking. These extraneous but unavoidable factors are
called, aptly, "confounders." One last example: People who take
supplements are healthier than the population at large, but their
health probably has nothing whatsoever to do with the supplements they
take — which recent studies have suggested are worthless.
Supplement-takers are better-educated, more-affluent people who,
almost by definition, take a greater-than-normal interest in personal
health — confounding factors that probably account for their superior
health.

But if confounding factors of lifestyle bedevil comparative studies of
different populations, the supposedly more rigorous "prospective"
studies of large American populations suffer from their own arguably
even more disabling flaws. In these studies — of which the Women's
Health Initiative is the best known — a large population is divided
into two groups. The intervention group changes its diet in some
prescribed manner, while the control group does not. The two groups
are then tracked over many years to learn whether the intervention
affects relative rates of chronic disease.

When it comes to studying nutrition, this sort of extensive, long-term
clinical trial is supposed to be the gold standard. It certainly
sounds sound. In the case of the Women's Health Initiative, sponsored
by the National Institutes of Health, the eating habits and health
outcomes of nearly 49,000 women (ages 50 to 79 at the beginning of the
study) were tracked for eight years. One group of the women were told
to reduce their consumption of fat to 20 percent of total calories.
The results were announced early last year, producing front-page
headlines of which the one in this newspaper was typical: "Low-Fat
Diet Does Not Cut Health Risks, Study Finds." And the cloud of
nutritional confusion over the country darkened.

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.

Note that these ecological relationships are between eaters and whole
foods, not nutrients. Even though the foods in question eventually get
broken down in our bodies into simple nutrients, as corn is reduced to
simple sugars, the qualities of the whole food are not unimportant —
they govern such things as the speed at which the sugars will be
released and absorbed, which we're coming to see as critical to
insulin metabolism. Put another way, our bodies have a longstanding
and sustainable relationship to corn that we do not have to
high-fructose corn syrup. Such a relationship with corn syrup might
develop someday (as people evolve superhuman insulin systems to cope
with regular floods of fructose and glucose), but for now the
relationship leads to ill health because our bodies don't know how to
handle these biological novelties. In much the same way, human bodies
that can cope with chewing coca leaves — a longstanding relationship
between native people and the coca plant in South America — cannot
cope with cocaine or crack, even though the same "active ingredients"
are present in all three. Reductionism as a way of understanding food
or drugs may be harmless, even necessary, but reductionism in practice
can lead to problems.

Looking at eating through this ecological lens opens a whole new
perspective on exactly what the Western diet is: a radical and rapid
change not just in our foodstuffs over the course of the 20th century
but also in our food relationships, all the way from the soil to the
meal. The ideology of nutritionism is itself part of that change. To
get a firmer grip on the nature of those changes is to begin to know
how we might make our relationships to food healthier. These changes
have been numerous and far-reaching, but consider as a start these
four large-scale ones:

From Whole Foods to Refined. The case of corn points up one of the key
features of the modern diet: a shift toward increasingly refined
foods, especially carbohydrates. Call it applied reductionism. Humans
have been refining grains since at least the Industrial Revolution,
favoring white flour (and white rice) even at the price of lost
nutrients. Refining grains extends their shelf life (precisely because
it renders them less nutritious to pests) and makes them easier to
digest, by removing the fiber that ordinarily slows the release of
their sugars. Much industrial food production involves an extension
and intensification of this practice, as food processors find ways to
deliver glucose — the brain's preferred fuel — ever more swiftly and
efficiently. Sometimes this is precisely the point, as when corn is
refined into corn syrup; other times it is an unfortunate byproduct of
food processing, as when freezing food destroys the fiber that would
slow sugar absorption.

So fast food is fast in this other sense too: it is to a considerable
extent predigested, in effect, and therefore more readily absorbed by
the body. But while the widespread acceleration of the Western diet
offers us the instant gratification of sugar, in many people (and
especially those newly exposed to it) the "speediness" of this food
overwhelms the insulin response and leads to Type II diabetes. As one
nutrition expert put it to me, we're in the middle of "a national
experiment in mainlining glucose." To encounter such a diet for the
first time, as when people accustomed to a more traditional diet come
to America, or when fast food comes to their countries, delivers a
shock to the system. Public-health experts call it "the nutrition
transition," and it can be deadly.

From Complexity to Simplicity. If there is one word that covers nearly
all the changes industrialization has made to the food chain, it would
be simplification. Chemical fertilizers simplify the chemistry of the
soil, which in turn appears to simplify the chemistry of the food
grown in that soil. Since the widespread adoption of synthetic
nitrogen fertilizers in the 1950s, the nutritional quality of produce
in America has, according to U.S.D.A. figures, declined significantly.
Some researchers blame the quality of the soil for the decline; others
cite the tendency of modern plant breeding to select for industrial
qualities like yield rather than nutritional quality. Whichever it is,
the trend toward simplification of our food continues on up the chain.
Processing foods depletes them of many nutrients, a few of which are
then added back in through "fortification": folic acid in refined
flour, vitamins and minerals in breakfast cereal. But food scientists
can add back only the nutrients food scientists recognize as
important. What are they overlooking?

Simplification has occurred at the level of species diversity, too.
The astounding variety of foods on offer in the modern supermarket
obscures the fact that the actual number of species in the modern diet
is shrinking. For reasons of economics, the food industry prefers to
tease its myriad processed offerings from a tiny group of plant
species, corn and soybeans chief among them. Today, a mere four crops
account for two-thirds of the calories humans eat. When you consider
that humankind has historically consumed some 80,000 edible species,
and that 3,000 of these have been in widespread use, this represents a
radical simplification of the food web. Why should this matter?
Because humans are omnivores, requiring somewhere between 50 and 100
different chemical compounds and elements to be healthy. It's hard to
believe that we can get everything we need from a diet consisting
largely of processed corn, soybeans, wheat and rice.

From Leaves to Seeds. It's no coincidence that most of the plants we
have come to rely on are grains; these crops are exceptionally
efficient at transforming sunlight into macronutrients — carbs, fats
and proteins. These macronutrients in turn can be profitably
transformed into animal protein (by feeding them to animals) and
processed foods of every description. Also, the fact that grains are
durable seeds that can be stored for long periods means they can
function as commodities as well as food, making these plants
particularly well suited to the needs of industrial capitalism.

The needs of the human eater are another matter. An oversupply of
macronutrients, as we now have, itself represents a serious threat to
our health, as evidenced by soaring rates of obesity and diabetes. But
the undersupply of micronutrients may constitute a threat just as
serious. Put in the simplest terms, we're eating a lot more seeds and
a lot fewer leaves, a tectonic dietary shift the full implications of
which we are just beginning to glimpse. If I may borrow the
nutritionist's reductionist vocabulary for a moment, there are a host
of critical micronutrients that are harder to get from a diet of
refined seeds than from a diet of leaves. There are the antioxidants
and all the other newly discovered phytochemicals (remember that sprig
of thyme?); there is the fiber, and then there are the healthy omega-3
fats found in leafy green plants, which may turn out to be most
important benefit of all.

Most people associate omega-3 fatty acids with fish, but fish get them
from green plants (specifically algae), which is where they all
originate. Plant leaves produce these essential fatty acids
("essential" because our bodies can't produce them on their own) as
part of photosynthesis. Seeds contain more of another essential fatty
acid: omega-6. Without delving too deeply into the biochemistry, the
two fats perform very different functions, in the plant as well as the
plant eater. Omega-3s appear to play an important role in neurological
development and processing, the permeability of cell walls, the
metabolism of glucose and the calming of inflammation. Omega-6s are
involved in fat storage (which is what they do for the plant), the
rigidity of cell walls, clotting and the inflammation response. (Think
of omega-3s as fleet and flexible, omega-6s as sturdy and slow.) Since
the two lipids compete with each other for the attention of important
enzymes, the ratio between omega-3s and omega-6s may matter more than
the absolute quantity of either fat. Thus too much omega-6 may be just
as much a problem as too little omega-3.

And that might well be a problem for people eating a Western diet. As
we've shifted from leaves to seeds, the ratio of omega-6s to omega-3s
in our bodies has shifted, too. At the same time, modern
food-production practices have further diminished the omega-3s in our
diet. Omega-3s, being less stable than omega-6s, spoil more readily,
so we have selected for plants that produce fewer of them; further,
when we partly hydrogenate oils to render them more stable, omega-3s
are eliminated. Industrial meat, raised on seeds rather than leaves,
has fewer omega-3s and more omega-6s than preindustrial meat used to
have. And official dietary advice since the 1970s has promoted the
consumption of polyunsaturated vegetable oils, most of which are high
in omega-6s (corn and soy, especially). Thus, without realizing what
we were doing, we significantly altered the ratio of these two
essential fats in our diets and bodies, with the result that the ratio
of omega-6 to omega-3 in the typical American today stands at more
than 10 to 1; before the widespread introduction of seed oils at the
turn of the last century, it was closer to 1 to 1.

The role of these lipids is not completely understood, but many
researchers say that these historically low levels of omega-3 (or,
conversely, high levels of omega-6) bear responsibility for many of
the chronic diseases associated with the Western diet, especially
heart disease and diabetes. (Some researchers implicate omega-3
deficiency in rising rates of depression and learning disabilities as
well.) To remedy this deficiency, nutritionism classically argues for
taking omega-3 supplements or fortifying food products, but because of
the complex, competitive relationship between omega-3 and omega-6,
adding more omega-3s to the diet may not do much good unless you also
reduce your intake of omega-6.

From Food Culture to Food Science. The last important change wrought
by the Western diet is not, strictly speaking, ecological. But the
industrialization of our food that we call the Western diet is
systematically destroying traditional food cultures. Before the modern
food era — and before nutritionism — people relied for guidance about
what to eat on their national or ethnic or regional cultures. We think
of culture as a set of beliefs and practices to help mediate our
relationship to other people, but of course culture (at least before
the rise of science) has also played a critical role in helping
mediate people's relationship to nature. Eating being a big part of
that relationship, cultures have had a great deal to say about what
and how and why and when and how much we should eat. Of course when it
comes to food, culture is really just a fancy word for Mom, the figure
who typically passes on the food ways of the group — food ways that,
although they were never "designed" to optimize health (we have many
reasons to eat the way we do), would not have endured if they did not
keep eaters alive and well.

The sheer novelty and glamour of the Western diet, with its 17,000 new
food products introduced every year, and the marketing muscle used to
sell these products, has overwhelmed the force of tradition and left
us where we now find ourselves: relying on science and journalism and
marketing to help us decide questions about what to eat. Nutritionism,
which arose to help us better deal with the problems of the Western
diet, has largely been co-opted by it, used by the industry to sell
more food and to undermine the authority of traditional ways of
eating. You would not have read this far into this article if your
food culture were intact and healthy; you would simply eat the way
your parents and grandparents and great-grandparents taught you to
eat. The question is, Are we better off with these new authorities
than we were with the traditional authorities they supplanted? The
answer by now should be clear.

It might be argued that, at this point in history, we should simply
accept that fast food is our food culture. Over time, people will get
used to eating this way and our health will improve. But for natural
selection to help populations adapt to the Western diet, we'd have to
be prepared to let those whom it sickens die. That's not what we're
doing. Rather, we're turning to the health-care industry to help us
"adapt." Medicine is learning how to keep alive the people whom the
Western diet is making sick. It's gotten good at extending the lives
of people with heart disease, and now it's working on obesity and
diabetes. Capitalism is itself marvelously adaptive, able to turn the
problems it creates into lucrative business opportunities: diet pills,
heart-bypass operations, insulin pumps, bariatric surgery. But while
fast food may be good business for the health-care industry, surely
the cost to society — estimated at more than $200 billion a year in
diet-related health-care costs — is unsustainable.

BEYOND NUTRITIONISM

To medicalize the diet problem is of course perfectly consistent with
nutritionism. So what might a more ecological or cultural approach to
the problem recommend? How might we plot our escape from nutritionism
and, in turn, from the deleterious effects of the modern diet? In
theory nothing could be simpler — stop thinking and eating that way —
but this is somewhat harder to do in practice, given the food
environment we now inhabit and the loss of sharp cultural tools to
guide us through it. Still, I do think escape is possible, to which
end I can now revisit — and elaborate on, but just a little — the
simple principles of healthy eating I proposed at the beginning of
this essay, several thousand words ago. So try these few (flagrantly
unscientific) rules of thumb, collected in the course of my
nutritional odyssey, and see if they don't at least point us in the
right direction.

1. Eat food. Though in our current state of confusion, this is much
easier said than done. So try this: Don't eat anything your
great-great-grandmother wouldn't recognize as food. (Sorry, but at
this point Moms are as confused as the rest of us, which is why we
have to go back a couple of generations, to a time before the advent
of modern food products.) There are a great many foodlike items in the
supermarket your ancestors wouldn't recognize as food (Go-Gurt?
Breakfast-cereal bars? Nondairy creamer?); stay away from these.

2. Avoid even those food products that come bearing health claims.
They're apt to be heavily processed, and the claims are often dubious
at best. Don't forget that margarine, one of the first industrial
foods to claim that it was more healthful than the traditional food it
replaced, turned out to give people heart attacks. When Kellogg's can
boast about its Healthy Heart Strawberry Vanilla cereal bars, health
claims have become hopelessly compromised. (The American Heart
Association charges food makers for their endorsement.) Don't take the
silence of the yams as a sign that they have nothing valuable to say
about health.

3. Especially avoid food products containing ingredients that are a)
unfamiliar, b) unpronounceable c) more than five in number — or that
contain high-fructose corn syrup.None of these characteristics are
necessarily harmful in and of themselves, but all of them are reliable
markers for foods that have been highly processed.

4. Get out of the supermarket whenever possible. You won't find any
high-fructose corn syrup at the farmer's market; you also won't find
food harvested long ago and far away. What you will find are fresh
whole foods picked at the peak of nutritional quality. Precisely the
kind of food your great-great-grandmother would have recognized as
food.

5. Pay more, eat less. The American food system has for a century
devoted its energies and policies to increasing quantity and reducing
price, not to improving quality. There's no escaping the fact that
better food — measured by taste or nutritional quality (which often
correspond) — costs more, because it has been grown or raised less
intensively and with more care. Not everyone can afford to eat well in
America, which is shameful, but most of us can: Americans spend, on
average, less than 10 percent of their income on food, down from 24
percent in 1947, and less than the citizens of any other nation. And
those of us who can afford to eat well should. Paying more for food
well grown in good soils — whether certified organic or not — will
contribute not only to your health (by reducing exposure to
pesticides) but also to the health of others who might not themselves
be able to afford that sort of food: the people who grow it and the
people who live downstream, and downwind, of the farms where it is
grown.

"Eat less" is the most unwelcome advice of all, but in fact the
scientific case for eating a lot less than we currently do is
compelling. "Calorie restriction" has repeatedly been shown to slow
aging in animals, and many researchers (including Walter Willett, the
Harvard epidemiologist) believe it offers the single strongest link
between diet and cancer prevention. Food abundance is a problem, but
culture has helped here, too, by promoting the idea of moderation.
Once one of the longest-lived people on earth, the Okinawans practiced
a principle they called "Hara Hachi Bu": eat until you are 80 percent
full. To make the "eat less" message a bit more palatable, consider
that quality may have a bearing on quantity: I don't know about you,
but the better the quality of the food I eat, the less of it I need to
feel satisfied. All tomatoes are not created equal.

6. Eat mostly plants, especially leaves. Scientists may disagree on
what's so good about plants — the antioxidants? Fiber? Omega-3s? — but
they do agree that they're probably really good for you and certainly
can't hurt. Also, by eating a plant-based diet, you'll be consuming
far fewer calories, since plant foods (except seeds) are typically
less "energy dense" than the other things you might eat. Vegetarians
are healthier than carnivores, but near vegetarians ("flexitarians")
are as healthy as vegetarians. Thomas Jefferson was on to something
when he advised treating meat more as a flavoring than a food.

7. Eat more like the French. Or the Japanese. Or the Italians. Or the
Greeks. Confounding factors aside, people who eat according to the
rules of a traditional food culture are generally healthier than we
are. Any traditional diet will do: if it weren't a healthy diet, the
people who follow it wouldn't still be around. True, food cultures are
embedded in societies and economies and ecologies, and some of them
travel better than others: Inuit not so well as Italian. In borrowing
from a food culture, pay attention to how a culture eats, as well as
to what it eats. In the case of the French paradox, it may not be the
dietary nutrients that keep the French healthy (lots of saturated fat
and alcohol?!) so much as the dietary habits: small portions, no
seconds or snacking, communal meals — and the serious pleasure taken
in eating. (Worrying about diet can't possibly be good for you.) Let
culture be your guide, not science.

8. Cook. And if you can, plant a garden. To take part in the intricate
and endlessly interesting processes of providing for our sustenance is
the surest way to escape the culture of fast food and the values
implicit in it: that food should be cheap and easy; that food is fuel
and not communion. The culture of the kitchen, as embodied in those
enduring traditions we call cuisines, contains more wisdom about diet
and health than you are apt to find in any nutrition journal or
journalism. Plus, the food you grow yourself contributes to your
health long before you sit down to eat it. So you might want to think
about putting down this article now and picking up a spatula or hoe.

9. Eat like an omnivore. Try to add new species, not just new foods,
to your diet. The greater the diversity of species you eat, the more
likely you are to cover all your nutritional bases. That of course is
an argument from nutritionism, but there is a better one, one that
takes a broader view of "health." Biodiversity in the diet means less
monoculture in the fields. What does that have to do with your health?
Everything. The vast monocultures that now feed us require tremendous
amounts of chemical fertilizers and pesticides to keep from
collapsing. Diversifying those fields will mean fewer chemicals,
healthier soils, healthier plants and animals and, in turn, healthier
people. It's all connected, which is another way of saying that your
health isn't bordered by your body and that what's good for the soil
is probably good for you, too.

URL: <http://www.nytimes.com/2007/01/28/magazine/28nutritionism.t.html?_r=1>

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