In Defense of Food Page 18
DON’T LOOK FOR THE MAGIC BULLET IN THE TRADITIONAL DIET. In the same way that foods are more than the sum of their nutrient parts, dietary patterns seem to be more than the sum of the foods that comprise them. Oceans of ink have been spilled attempting to tease out and analyze the components of the Mediterranean diet, hoping to identify the X factor responsible for its healthfulness: Is it the olive oil? The fish? The wild greens? The garlic? The nuts? The French paradox too has been variously attributed to the salutary effects of red wine, olive oil, and even foie gras (liver is high in B vitamins and iron). Yet when researchers extract a single food from a diet of proven value, it usually fails to adequately explain why the people living on that diet live longer or have lower rates of heart disease or cancer than people eating a modern Western diet. The whole of a dietary pattern is evidently greater than the sum of its parts.
Some of these dietary parts flagrantly contradict current scientific thinking about healthy eating. By the standards of most official dietary guidelines, the French eat poorly: way too much saturated fat and wine. The Greeks too have their own paradox; defying the recommendation that we get no more than 30 percent of our calories from fats, they get 40 percent, most of it in the form of olive oil. So researchers begin looking for synergies between nutrients: Might the antioxidants in the red wine help metabolize the fats? Perhaps. But it seems unlikely that any single food, nutrient, or mechanism will ever explain the French paradox; more likely, we will someday come to realize there never was a paradox. Dietary paradoxes are best thought of as breakdowns in nutritionist thinking, a sign of something wrong with the scientific consensus rather than the diet in question.
But the quest to pin down the X factor in the diets of healthy populations (PubMed, a scholarly index to scientific articles on medicine, lists 257 entries under “French Paradox” and another 828 under “Mediterranean Diet”) goes on, because reductionist science is understandably curious and nutritionism demands it. If the secret ingredient could be identified, then processed foods could be reengineered to contain more of it, and we could go on eating much as before. The only way to profit from the wisdom of traditional diets (aside from writing books about them) is to break them down using reductionist science and then sell them for their nutrient parts.
In recent years a less reductive method of doing nutritional science has emerged, based on the idea of studying whole dietary patterns instead of individual foods or nutrients. The early results have tended to support the idea that traditional diets do indeed protect us from chronic disease and that these diets can be transferred from one place and population to another. Even some of the researchers associated with the Nurses’ Health Study have begun doing dietary pattern analysis, in one case comparing a prudent diet modeled on Mediterranean and Asian patterns-high in fruits, vegetables, and fish and low in red meat and dairy products-with a typical Western diet featuring lots of meat (and processed meat), refined grains, sugary foods, french fries, and dairy products. (The study found “strong evidence” that the prudent dietary pattern may reduce the risk of coronary heart disease.)* Another recent study of a traditional plant-based diet found that even when you tested it against a low-fat Western diet that contained the same proportions of total fat, saturated fat, protein, carbohydrates, and cholesterol, the people on the traditional diet did much better by an important measure of cardiovascular health. What this suggests is that the addition of certain foods to the diet (Vegetables and fruits? Whole grains? Garlic?) may be more important than the subtraction of the usual nutritional suspects.*
As the authors of the first study point out, the strength of such an approach is that “it more closely parallels the real world” in that “it can take into account complicated interactions among nutrients and non-nutrient substances in studies of free-living people.” The weakness of such an approach is that “it cannot be specific about the particular nutrients responsible” for whatever health effects have been observed. Of course, this is a weakness only from the perspective of nutritionism. The inability to pin down the key nutrient matters much more to the scientist (and the food industry) than it does to us “free-living” eaters in the real world.
HAVE A GLASS OF WINE WITH DINNER. Wine may not be the X factor in the French or Mediterranean diet, but it does seem to be an integral part of those dietary patterns. There is now abundant scientific evidence for the health benefits of alcohol to go with a few centuries of traditional belief and anecdotal evidence. Mindful of the social and health effects of alcoholism, public health authorities are loath to recommend drinking, but the fact is that people who drink moderately and regularly live longer and suffer considerably less heart disease than teetotalers. Alcohol of any kind appears to reduce the risk of heart disease, but the polyphenols in red wine (resveratrol in particular) appear to have unique protective qualities. The benefits to your heart increase with the amount of alcohol consumed up to about four drinks a day (depending on your size), yet drinking that much increases your risk of dying from other causes (including certain cancers and accidents), so most experts recommend no more than two drinks a day for men, one for women. The health benefits of alcohol may depend as much on the pattern of drinking as on the amount: Drinking a little every day is better than drinking a lot on the weekends, and drinking with food is better than drinking without it. (Food blunts some of the deleterious effects of alcohol by slowing its absorption.) Also, a diet particularly rich in plant foods, as the French and Mediterranean diets are, supplies precisely the B vitamins that drinking alcohol depletes. How fortunate! Someday science may comprehend all the complex synergies at work in a traditional diet that includes wine, but until then we can marvel at its accumulated wisdom-and raise a glass to paradox.
FOUR - NOT TOO MUCH: HOW TO EAT
I f a food is more than the sum of its nutrients and a diet is more than the sum of its foods, it follows that a food culture is more than the sum of its menus-it embraces as well the set of manners, eating habits, and unspoken rules that together govern a people’s relationship to food and eating. How a culture eats may have just as much of a bearing on health as what a culture eats. The foodstuffs of another people are often easier to borrow than their food habits, it’s true, but to adopt some of these habits would do at least as much for our health and happiness as eaters.
What nutritionism sees when it looks at the French paradox is a lot of slender French people eating gobs of saturated fat washed down w
ith wine. What it fails to see is a people with a completely different relationship to food than we have. Nutritionists pay far more attention to the chemistry of food than to the sociology or ecology of eating. All their studies of the benefits of red wine or foie gras overlook the fact that the French eat very differently than we do. They seldom snack, and they eat most of their food at meals shared with other people. They eat small portions and don’t come back for seconds. And they spend considerably more time eating than we do. Taken together, these habits contribute to a food culture in which the French consume fewer calories than we do, yet manage to enjoy them far more.
Paul Rozin has confirmed many of these observations in a comparison of French and American eating habits conducted in restaurants in Paris and Philadelphia. Rozin focused on portion size and time spent eating. He found that serving sizes in France, both in restaurants and supermarkets, are considerably smaller than they are in the United States. This matters because most people have what psychologists call a unit bias-we tend to believe that however big or small the portion served, that’s the proper amount to eat. Rozin also found that the French spend considerably more time enjoying their tiny servings than we do our Brobdingnagian ones. “Although they eat less than Americans,” Rozin writes, “the French spend more time eating, and hence get more food experience while eating less.” He suggests that the French gift for extracting more food experience from fewer calories may help explain why the French are slimmer and healthier than we are. This sounds like an eminently sensible approach to eating and suggests an overarching policy that might nudge us in that direction.
PAY MORE, EAT LESS. What the French case suggests is that there is a trade-off in eating between quantity and quality.
The American food system has for more than a century devoted its energies to quantity and price rather than to quality. Turning out vast quantities of so-so food sold in tremendous packages at a terrific price is what we do well. Yes, you can find exceptional food in America, and increasingly so, but historically the guiding principle has been, in the slogan of one supermarket chain, to “pile it high and sell it cheap.”
There’s no escaping the fact that better food-whether measured by taste or nutritional quality (which often correspond)-costs more, usually because it has been grown with more care and less intensively. Not everyone can afford to eat high-quality food in America, and that is shameful; however, those of us who can, should. Doing so benefits not only your health (by, among other things, reducing your exposure to pesticides and pharmaceuticals), but also the health of the people who grow the food as well as the people who live downstream and downwind of the farms where it is grown.
Another important benefit of paying more for better-quality food is that you’re apt to eat less of it.
“Eat less” is the most unwelcome advice of all, but in fact the scientific case for eating a lot less than we presently do is compelling, whether or not you are overweight. Calorie restriction has repeatedly been shown to slow aging and prolong lifespan in animals, and some researchers believe it is the single strongest link between a change in the diet and the prevention of cancer. Put simply: Overeating promotes cell division, and promotes it most dramatically in cancer cells; cutting back on calories slows cell division. It also stifles the production of free radicals, curbs inflammation, and reduces the risk of most of the Western diseases.
“Eat less” is easier said than done, however, particularly in a culture of cheap and abundant calories with no deeply rooted set of rules to curb overeating. But other cultures do have such rules and we can try to emulate them. The French have their modest portions and taboo against seconds. The people of Okinawa, one of the longest-lived and healthiest populations in the world, practice a principle they call hara hachi bu: Eat until you are 80 percent full.
This is a sensible idea, but also easier said than done: How in the world do you know when you’re 80 percent full? You’d need to be in closer touch with your senses than many Americans at the table have become. As Rozin and other psychologists have demonstrated, Americans typically eat not until they’re full (and certainly not until they’re 80 percent full) but rather until they receive some visual cue from their environment that it’s time to stop: the bowl or package is empty, the plate is clean, or the TV show is over. Brian Wansink, a Cornell professor of marketing and nutritional science who has done several ingenious studies on portion size and appetite, concludes that Americans pay much more attention to external than to internal cues about satiety.* By comparison the French, who seem to attend more closely to all the sensual dimensions of eating, also pay more attention to the internal cues telling us we feel full.
So how might paying more for food help us eat less of it? In two ways. It is well established that how much we eat is strongly influenced by the cost of food in terms of both the money and effort required to put it on the table. The rise in obesity in America began around 1980, exactly when a flood of cheap calories started coming off American farms, prompted by the Nixon-era changes in agricultural policy. American farmers produced 600 more calories per person per day in 2000 than they did in 1980. But some calories got cheaper than others: Since 1980, the price of sweeteners and added fats (most of them derived, respectively, from subsidized corn and subsidized soybeans) dropped 20 percent, while the price of fresh fruits and vegetables increased by 40 percent. It is the cheaper and less healthful of these two kinds of calories on which Americans have been gorging.
These are precisely the kinds of calories found in convenience food-snacks, microwavable entrйes, soft drinks, and packaged food of all kind-which happens to be the source of most of the 300 or so extra calories Americans have added to their daily diet since 1980. So these foods are cheap in a second sense too: They require very little, if any, time or effort to prepare, which is the other reason we eat more of them. How often would you eat french fries if you had to peel, wash, cut and fry them yourself-and then clean up the mess? Or ever eat Twinkies if you had to bake the little cakes and then squirt the filling into them and clean up?
Recently a group of Harvard economists seeking to advance an economic theory for the obesity epidemic correlated the rise in the average weight of Americans with a decline in the “time cost” of eating-cooking, cleaning up, and so on. They concluded that the widespread availability of cheap convenience foods could explain most of the twelve-pound increase in the weight of the average American since the early 1960s. They point out that in 1980 less than 10 percent of Americans owned a microwave; by 1999 that figure had
reached 83 percent of households. As technology reduces the time cost of food, we tend to eat more of it.*
My guess is that the converse still holds true, and that paying more for food-in every sense-will reduce the amount of it we eat. Several of the rules offered below are aimed in that direction. While it is true that many people simply can’t afford to pay more for food, either in money or time or both, many more of us can. After all, just in the last decade or two we’ve somehow found the time in the day to spend several hours on the Internet and the money in the budget not only to pay for broadband service, but to cover a second phone bill and a new monthly bill for television, formerly free. For the majority of Americans, spending more for better food is less a matter of ability than priority. We spend a smaller percentage of our income on food than any other industrialized society; surely if we decided that the quality of our food mattered, we could afford to spend a few more dollars on it a week-and eat a little less of it.
Is it just a coincidence that as the portion of our income spent on food has declined, spending on health care has soared? In 1960 Americans spent 17.5 percent of their income on food and 5.2 percent of national income on health care. Since then, those numbers have flipped: Spending on food has fallen to 9.9 percent, while spending on health care has climbed to 16 percent of national income. I have to think that by spending a little more on healthier food we could reduce the amount we have to spend on health care.