On the other side, people like T. Colin Campbell, the author of The China Study, Dr. Dean Ornish, and Dr. Caldwell Esselstyn argue that animal-based products create disease, that there are virtually no nutrients in animal-based foods that are not better provided by plants, and that the best health-promoting diet is a low-fat, vegetable and grain-based diet--a vegan diet.
The diversity of information can be confusing. The Paleo Diet turns to pre-agricultural history to suggest a diet reminiscent of our hunter and gatherer ancestors: Paleolithic humans. Inspired by a 1985 study on Paleolithic nutrition published in The New England Journal of Medicine, and perhaps more famously by Jared Diamond's 1987 article "The Worst Mistake in the History of the Human Race," the Paleo diet argues, essentially, that the human race, a product of millions of years of evolution, has not yet evolved the ability to digest and assimilate the products of agriculture: most notably, grains, beans, and legumes.
Diamond's article is not entirely about diet. He argues, for example, that the development of agriculture was a "mistake" because, when compared to our foraging ancestors, civilized people have suffered far more war, famine, and disease. In terms of diet, however, Diamond suggests the varied diet enjoyed by hunter-gatherers was superior to civilized people's dependence on limited crops. To support his claim, he cites evidence from the fossil record: a post-agricultural decline in height of Greek and Turkish people; a 50% increase in tooth defects; a fourfold increase in anemia; and a threefold increase in bone lesions among Indians.
This idea was not necessarily novel. In 1939, Weston Price had published a book, Nutritional and Physical Degeneration, that detailed a series of ethnographic studies based on diverse indigenous populations across the globe. Price claimed that diseases typical of Western culture did not exist in non-Western indigenous cultures, but as indigenous cultures adopted Western diets, they showed increases in Western diseases, specifically in dental caries (Weston A. Price was a dentist).
Price's findings were lauded and reviled. As Wikipedia notes, one journal called Price "The Charles Darwin of Nutrition." Yet, "a review in the Journal of the American Medical Association also disagreed with the significance of this nutritional research, noting Price was 'observant but not wholly unbiased' and that his approach was 'evangelistic rather than scientific.' "
Meanwhile, years later, as Jared Diamond was setting the anthropological world aflame--I still recall my first anthropology class in college, how my teacher spoke about Diamond's claims with heated passion, a passion still burning today--T. Colin Campbell was conducting his now-famous study. In 1983, he initiated initiated The China Project, "the most comprehensive study of nutrition ever," as his book on the study claims.
Interestingly, Campbell's basic premise, that traditional rural Chinese diets are more healthful than the diets enjoyed by the industrialized parts of China, agrees with Price's comparison between Western and non-Western indigenous diets.
However, Campbell comes to an opposing conclusion: diets high in animal protein are linked to "the diseases of affluence"--heart disease, cancer, and diabetes.
So, two very influential voices on nutrition, based on similar findings, come to completely different conclusions. Obviously, Campbell's research, conducted over the course of twenty years, and jointly by Cornell University, Oxford University, and the Chinese Academy of Preventive Medicine seems much more valid than the ethnographic studies of a dentist.
And yet, there is still no consensus on what constitutes a healthy diet. Nevertheless, grains and grain-based diets now dominate the world. Recently, too, the USDA introduced a new food pyramid, advocating more “Whole Grains.”
Most of these diets apply a blanket philosophy to a unique experience. A “whole grain” diet, for example, might be appropriate for some (say, those suffering from heart disease) and disastrous for others (a celiac, for example; or one who otherwise might have trouble digesting grains).
Some of these ideologies do come somewhat closer to addressing the individual’s unique needs. Within the context of his somewhat limited view of healthful eating, for example, Dr. Mercola states that “one person’s food may be another person’s poison,” and advocates a personalized nutrition plan. The “Eat Right for Your Type” diet encourages people to eat certain foods and avoid others based on their blood type.
When faced with bewildering possibilities, I try to seek the first possibility—the source. In diet, the source might refer to your ancestry and culture, as well as your environment—both local and bacterial. The source might also refer, of course, to your own body or body type.
What foods are best suited to your constitution? What foods will best fuel your unique lifestyle? More importantly, what foods do you enjoy? What foods do you digest easily? What foods make you feel powerful, or light, or healthy?
Discovering the answers to these questions can have a tremendously beneficial influence on your relationship with food. These answers will help you see past the confusion of “diets.” These answers might even help you discover your own perfect diet.
What Did Your Ancestors Eat and Why?
When I was diagnosed with ulcerative colitis, at twenty-six, I learned that those from an Ashkenazi background suffered an increased rate of the illness.
I wondered, then, if the Ashkenazi diet might have contributed to the disease; or, perhaps the diet had evolved to counteract digestive problems. A general survey offered no definitive answer. To discover the truth, I had to go to the actual source: my grandparents. What I discovered was that my ancestors, indeed, had suffered a history of digestive problems, and that to combat these problems they had learned to avoid certain foods, such as raw foods, and had naturally gravitated to easier-to-digest foods, such as chicken, chicken fat (schmaltz), white rice, sourdough bread, and kasha.
At the time of this discovery, I was a vegetarian who ate a predominantly raw-food diet. I, however, did not feel sufficiently motivated to adapt my diet—a terrible mistake, which led, I believe, to years of needless suffering, and eventually to a diagnosis of type-1 diabetes. I often wonder: how might my life had been different had I paid attention to the wisdom of my ancestor’s diet—to what my ancestors had to tell me about diet?
What is Your Local Food Culture?
The Bronx, Queens, or Long Island Sound,
Even other states come right and exact,
It ain't where you're from, it's where you're at.
~Erik B. & Rakim
Culture is an amalgam of influences, including ancestry, but our food culture is often defined more comprehensively by our local environment: the weather and the people, the soil and the preoccupations of the people, the landscape and the music, even the bacteria.
You might view your food culture as it relates to local food: the food grown, cooked, and enjoyed close to your home. But what does “local” mean? Food grown in your garden is the most local. Then, food grown in your community, state, region, and country might be considered local. For certain parts of the year, or for products that thrive locally, it may be possible to buy close to home. At other times, or for less common products, an expanded reach may be required. During the winter, our best “local” fruit option (here in the Philadelphia region) is Florida’s citrus fruits.
The best way engage with your local food culture is to buy and cook local produce. Local produce offers an introduction to eating seasonally—and an excellent way to learn about local agriculture. You might also seek local meat or dairy. In Pennsylvania, a great resource for local food is the website www.buylocalpa.org. In the Philadelphia region, we’re lucky to call Fair Food Philly our own. The Fair Food website (www.fairfoodphilly.org) describes their mission like this: “At Fair Food, we dedicate ourselves to bringing healthy local food to the marketplace and promoting a humane, sustainable agriculture system for the region.”
How Does Environment Influence Your Diet?
Across the world, various cultures have adapted idiosyncratic diets in response to environment. Traditionally, Inuits consume an average of 75% of their daily energy intake from fat. An article in Discover Magazine described the circumstances shaping this diet:
“Shaped by glacial temperatures, stark landscapes, and protracted winters, the traditional Eskimo diet had little in the way of plant food, no agricultural or dairy products, and was unusually low in carbohydrates.”
To the typical American view, this does not necessarily seem like the healthiest diet. Many doctors have apparently linked high-fat diets with disease. (An important caveat in evaluating any food-related study: what was the food source?) And yet, traditionally, Inuits enjoyed great health. The Discover Magazine article calls this the “Inuit Paradox.”
"What the diet of the Far North illustrates...is that there are no essential foods—only essential nutrients. And humans can get those nutrients from diverse and eye-opening sources. One might, for instance, imagine gross vitamin deficiencies arising from a diet with scarcely any fruits and vegetables. What furnishes vitamin A, vital for eyes and bones? We derive much of ours from colorful plant foods, constructing it from pigmented plant precursors called carotenoids (as in carrots). But vitamin A, which is oil soluble, is also plentiful in the oils of cold-water fishes and sea mammals, as well as in the animals’ livers, where fat is processed. These dietary staples also provide vitamin D, another oil-soluble vitamin needed for bones. Those of us living in temperate and tropical climates, on the other hand, usually make vitamin D indirectly by exposing skin to strong sun—hardly an option in the Arctic winter—and by consuming fortified cow’s milk, to which the indigenous northern groups had little access until recent decades and often don’t tolerate all that well."
Your Bacterial Ecosystem: The Most Local Environment Possible
The human body is saturated with microbes. As the New Yorker states, “Nearly all DNA in our bodies belongs to microorganisms: they outnumber our cells nine to one.” You might look at your body, inside and out, as a microbial ecosystem. This ecosystem is not dependent on genes, however: it is entirely dependent on environment. NPR reports:
"Whose genes matter most to you? Your mom's? Your dad's? Or genes inside the trillions of bacteria living in your intestine, your mouth, your nasal passages and a lot of places we'd rather not mention? The answer: Obviously, your parents' genes matter, but it turns out we humans have two sets of genes in us: the ones we inherited from our human ancestors and the ones that walk in through our mouths starting when we're just hours old…Not surprisingly, a person who grows up in Argentina and another who grows up in northern Alaska tend to acquire different bacteria in their intestines and mouths — and, stunningly, these differences seem to matter."
This might account for why cultures not only eat different foods but their digestive systems use these foods in different ways. The Inuits eat more fat than most populations “but their gastrointestinal systems apparently are more capable of breaking fats down for use by their bodies.”
It is important to remember: Most bacteria are not harmful, although some bacteria can have negative influences. It is important that the balance of microbes be maintained to favor the beneficial bacteria over the potentially harmful ones. This is why probiotics can be so important. Probiotics increase the ratio of “good” bacteria in your gut.
The science supporting the use of probiotics is impressive. The gut is a prominent part of the immune system. Several fascinating recent studies (like this one) indicate that supplementation with probiotics can positively influence the immune system. This might be especially helpful for those suffering from auto-immune conditions, like type-1 diabetes, ulcerative colitis, psoriasis, or rheumatoid arthritis. The gut also plays a prominent role in mood--a recent famous study suggests that the presence of absence of probiotics might even modulate mood (I’ve personally found this to be true). Probiotics might also have an effect on weight.