“To understand is to perceive patterns.”

—Isaiah Berlin, The Proper Study of Mankind: An Anthology of Essays

Consider this scenario for a moment. If someone offered you a pill that had been shown to prevent and reverse heart disease and type 2 diabetes; lower cholesterol, blood pressure, and body weight; significantly reduce your risk of getting multiple types of cancer; extend your life span; and make you look and feel great, would you hesitate to take it? It may not come in a bottle, but, as you will see in this book, a whole foods, plant-based diet has been shown to do all these things.

On the other hand, consider the following scientific findings. High consumption of red meat and processed meats has been connected with greater risk of death from all causes, including chronic diseases such as cardiovascular disease and type 2 diabetes.¹ Eating large amounts of animal protein has been correlated with higher incidences of cancer² and mortality.³ More than a thousand studies on bowel cancer risk have confirmed that red meat increases risk while high-fiber plant foods decrease it.⁴ Processed meats are particularly scary, with significant studies linking them to stomach cancer, breast cancer, and colon cancer, and the World Health Organization classifying them as a carcinogen.⁵ As a result, the World Cancer Research Fund International and the American Institute for Cancer Research came out with firm recommendations for people to “eat mostly foods of plant origin,”⁶ including whole grains, fruits, vegetables, and beans.

These studies are not simply outliers. In fact, they are just a few among a multitude of compelling data points that make the case for a whole foods, plant-based diet. The research supporting the wisdom of this way of eating, even briefly summarized, is enough to fill several books. Rigorous laboratory experiments, carefully controlled clinical trials, and long-term observational studies following millions of people over several decades confirm the profound value of eating more real plant-based foods and minimizing highly processed foods and animal products.

Challenging American Dietary Dogma: The China Study

Scientists have various methods at their disposal when it comes to studying diet, health, and longevity. They can study a population of healthy people, perform controlled studies on two groups eating different diets, or isolate nutrients for examination in the laboratory. Any of these approaches could be called “nutritional science,” but they are so distinct that they might as well be different fields. Some look at the big picture, seeking patterns and trends; others focus on detailed, specific chemical processes. Each method offers valid and important insights into the riddle of health, and each also has its limitations and blind spots. While most scientists stake their entire careers on one particular type of research, occasionally you meet a rare inquirer whose quest for knowledge has included both the macro and the micro, the big picture and the isolated details. T. Colin Campbell is one such man.

If the field of nutrition had an aristocracy, Campbell would surely be part of it. He may not have been the first to demonstrate significant connections between diet and disease, but he did so on a scale that was unmatched. His career-defining work was known as The China Study (or The China-Cornell-Oxford Project, to give it its full title)—a massive twenty-year epidemiological study that examined the eating habits and diseases of 6,500 people in sixty-five Chinese provinces. A 1990 New York Times article called it “the most comprehensive large study ever undertaken of the relationship between diet and the risk of developing disease” and reported that even its early findings were “challenging much of American dietary dogma.”7

What were Campbell’s controversial findings? He sums up the essential message this way: “People who ate the most animal-based foods got the most chronic disease.… People who ate the most plant-based foods were the healthiest and tended to avoid chronic disease.”⁸

Campbell would once have seemed an unlikely candidate to become an advocate for plant-based eating. Growing up on a dairy farm in the beautiful Virginia countryside, the young Campbell believed that “the good old American diet is the best there is. The more dairy, meat, and eggs we consumed, the better.”⁹ After studying at Penn State, Cornell, and MIT, and teaching at Virginia Tech, he returned to Cornell as a professor in 1975. He helped set nutritional policy guidelines, provided information for and sat on governmental committees, generated key original research funded by top institutions, set standards for health programs, and developed policy for international food and nutrition programs. And yet, even as he ascended to the top of the health and nutrition establishment, he was beginning to question its tenets.

Campbell slowly began to suspect that the meat- and dairy-heavy American diet was playing a significant role in the epidemics of heart disease, cancer, and diabetes. By the late 1970s, he had shown strong evidence in his laboratory that certain nutrients, including proteins derived from animal-based foods, were involved in promoting the development of cancerous tumors in animals. Plant-based foods, on the other hand, seemed to be a factor in decreasing tumor development. These studies, however, were limited to animals, and they focused on specific, isolated nutrients in carefully controlled circumstances. “Nutrient by nutrient. That’s the way we did research, that’s the way I taught it,”10 Campbell says. And this form of research has its limits. Each nutrient interacts with other nutrients in a thousand different ways, and the more we seek to isolate one and vigilantly rule out all these various interdependent relationships, the more we distance ourselves from nutrition in the real world. As Campbell told the New York Times, “I came to believe… that there was a very different world of understanding nutrition. We shouldn’t be thinking in a linear way that A causes B. We should be thinking about how things work together.”¹¹ And to be able to study how things worked together, he needed to follow a large population over a long period of time.

Around this time, Campbell met a Chinese scientist, Dr. Chen Junshi, who would provide just that opportunity. Junshi told Campbell that in the early 1970s, Zhou Enlai, premier of the People’s Republic of China, had been dying of cancer and had initiated the China Health and Nutrition Survey, the largest survey of its kind ever completed.

The survey—which had collected data from 880 million Chinese citizens, or 96% of the population—showed fascinating patterns. Cancer rates, it revealed, were often geographic in nature. In some rural areas there was little or no evidence of the disease, while other regions, particularly urban ones, showed dramatic increases. Inspired by the breadth of this data, Campbell and Junshi proposed an extensive survey of dietary and lifestyle habits.

Late-twentieth-century China offered a uniquely fertile ground for a study of diet and disease. The population was genetically very similar, but varied significantly in dietary habits, disease rates, and other environmental factors from region to region. In sixty-five rural and semirural regions of China, Campbell and his team administered questionnaires, took blood and urine samples, analyzed foods from local markets, and carefully measured participating families’ food intake over a period of a few days. “When we were done,” Campbell writes, “we had more than 8,000 statistically significant associations between lifestyle, diet, and disease variables.”12

What did The China Study show? It conclusively demonstrated that the regions in which people ate the most animal products, which tended to be the wealthiest regions, had the highest rates of heart disease, cancer, and other chronic degenerative diseases, leading Campbell to call them “diseases of affluence.” In contrast, in the regions of greater poverty, people ate fewer animal foods and had lower rates of these diseases.

What specifically caused these diseases of affluence? Was it the saturated fat found in animal foods? Was it animal protein itself or a particular type of animal meat? Was it dietary cholesterol, which is found only in animal foods? These are questions that were beyond the scope of Campbell’s research. Still, it’s impossible not to notice the striking relationships between higher consumption of animal products, the adoption of more Western-style diets, and higher rates of obesity, heart disease, cancer, and diabetes.

For those championing the health potential of whole foods, plant-based diets, The China Study has become an important touchstone. The book, written by Campbell and his son, Thomas Campbell, MD, was published in 2005, and has shocked the publishing world by selling close to two million copies. But the epidemiological approach to nutrition (see box, here) is not without its critics, many of whom don’t like this type of “observational” research. They claim that such studies cannot easily isolate particular foods or nutrients or assign clear causal links between a certain food and a certain outcome. They cannot eliminate other factors that might be playing a role, such as environmental conditions. They draw correlations and reveal patterns and trends, but correlation, as is often said, does not equal causation. Of course, it should be said that T. Colin Campbell, who has done every kind of nutritional research, is well aware of the scope and limitations of observational data.

Such criticisms are often combined with an insistence that randomized controlled trials (see box, here) are the only surefire means of resolving nutritional questions. We beg to differ. While RCTs are useful for testing drugs, their downside—and it’s a significant one—is that they do not easily lend themselves to the study of long-term dietary effects. The types of chronic disease that are diet related, such as heart disease and cancer, tend to develop slowly, over years and even decades. The much shorter time frames of more controlled studies (measured in months instead of years and decades) are often not sufficient to show the results that really matter. Furthermore, it is almost impossible to randomize people to follow specific diets over a long period, and often not ethically acceptable to do so, just as it was not acceptable to force nonsmokers to smoke for thirty years to determine “definitively” whether smoking was harmful. We would do well to remember that the evidence for the relationship between smoking and cancer came from epidemiological studies, and the tobacco industry used the “correlation is not causation” argument for years as a key weapon in its arsenal of rebuttals.

“The Healthiest People in the World”

The data from The China Study is extremely compelling, but are there other studies that have come to similar conclusions, ones that have been conducted a little closer to home? The answer is yes. One such group of studies has been derived from a unique population of Americans, the Seventh-day Adventists, a Christian religious sect established in the mid-nineteenth century. Many of the Adventists are inspired by the biblical verse Genesis 1:29: “And God said, Behold, I have given you every herb bearing seed, which is upon the face of all the earth, and every tree, in the which is the fruit of a tree yielding seed; to you it shall be for meat.” In other words, eat real foods, mostly plants.

The Adventists are one of the most interesting groups to study, from the perspective of diet, because they have such a similar overall lifestyle (some distinguishing factors being that there are very few smokers or alcohol consumers, they have a strong religious faith and community, and they exercise regularly), but at the same time, specific members follow different dietary patterns. These range from vegan (no animal products) to lacto-ovo vegetarian (vegetarian with dairy and eggs), to pesco-vegetarian (vegetarian with some fish) to meat-eaters. It is rare in epidemiological studies that researchers can observe a group of people with very similar lifestyles but so many distinct dietary subgroups, enabling them to more effectively isolate the impact of diet on health.

In the first Adventist study, conducted in the 1970s and ’80s in California, more than thirty-four thousand people were followed for fourteen years.13 The first thing that jumps out about the data is that the Adventists who ate a primarily plant-based diet—the vegans, lacto-ovo vegetarians, and pesco-vegetarians (collectively referred to by researchers as “the vegetarians”)—were the longest-lived populations, not just among their fellow Adventists, but among all Californians, and possibly in the world! In fact, Loma Linda, California—where there is a large community of Adventists—has been identified as one of the world’s five longevity hot spots, the “Blue Zones,” which we will discuss in chapter 4. For now, let us just say that the Adventists have a life span worth studying—the vegetarian men and women live to be about eighty-three and eighty-six, respectively (compared to seventy-six and eighty-one for the average American).¹⁴ And if you just look at those who also had healthy lifestyles, meaning no smoking, regular exercising, and so on, the average life span jumps to eighty-seven and ninety. That is an extra eleven years of life for men and nine for women!

When it comes to America’s leading causes of death—heart disease and cancer—the vegetarian Adventists again fare well. They have the lowest rate of heart disease in the nation.15 In men, the risk of fatal heart disease was “significantly related to beef intake.”¹⁶ The risk of colon cancer was increased by 88% in Adventists who ate meat over their vegetarian counterparts. Diabetes, our rapidly growing national epidemic, is rare among the Adventists. Indeed, they boast the nation’s lowest rates of the disease.¹⁷

Part of what make the Adventist Health Studies so remarkable is the geographical context of the population. For example, Loma Linda, California, is hardly tucked away on an isolated island, cut off from contemporary society’s dietary habits. No, it is right in the middle of southern California’s cultural melting pot, just south of the San Bernardino freeway. In other words, they live among us. And yet, healthwise, they might as well exist on a different planet. Indeed, their health outcomes are like a bright shining vision of possibility in the midst of America’s chronic disease dystopia.

We don’t all have time to become experts in nutritional science, so it’s understandable we turn to the popular media for bite-size, predigested versions. However, when it comes to something as important as what you eat, we encourage you to take a few extra steps to ensure you entrust your health to reliable sources of information.

1. Go to the Source

Don’t get fooled by a dramatic headline. Read the substance of the story and, if necessary, check out the actual study. You might be surprised how different they can be.

2. Ask Who’s Behind It

Unfortunately, too many food companies are initiating, funding, and even writing up the studies that make their products look good. A shocking percentage of studies published in leading medical journals are commercially funded.¹⁸ Of course, funding conflicts of interest don’t always indicate bad science, but never underestimate how simple it can be to design studies that obtain results favorable to particular interest groups.

3. Consider How Well It Is Designed

The devil is often in the details, and study design matters. Is butter good for you? If you design a study that compares it to margarine, the result may tell you more about the deficiency of margarine than the ultimate nutritional value of butter. Journalists regularly fall for this kind of thing, especially if it allows them to write a surprising or “shocking” headline.

4. Look for Backup

When it comes to nutrition, single studies must be looked at in light of larger trends. Are there corroborating studies? Don’t take any single study too seriously if it is only one of many on the subject; give the most credence to general trends. If a hundred studies implicate refined sugars in health troubles, and two outliers exonerate them, don’t use that as a justification to order dessert.

5. Find Trusted Sources

This final tip may be the most important. Very few of us have the time or expertise to research nutrition by ourselves. We must rely on trusted sources to give us the straight scoop. All the Whole Foodie Heroes we feature in this book have websites and books that you may find helpful in your quest for better health.

In 2002 a second major Adventist study was started, led by Dr. Gary Fraser and a team of researchers from Loma Linda University, which included ninety-six thousand participants from across the United States and Canada. The results from that study showed that Adventist meat-eaters had the biggest waistlines, and had a higher death rate than their vegetarian Adventist counterparts. They also tended to have worse overall dietary habits, including greater consumption of highly processed foods such as sugar, soda, and refined grains. This raises the question of whether it was the animal foods or the processed foods or both that led to shorter lives in this cohort. Although we cannot tease that out with this study, what we can tell is that the lacto-ovo vegetarians, the pesco-vegetarians, and the vegans all had significantly lower mortality rates compared to the meat-eaters.19

It’s worth noting that even those Adventists classified as meat-eaters were much less so than most Americans. The meat-eating Adventists’ diet (in terms of daily intake in grams) was largely composed of fruits and vegetables, nuts, legumes, and soy foods. And the overall better life expectancy of the community reflects that fact.

Vegan Doesn’t Necessarily Mean Healthy

It’s important to understand that one can adopt a vegan or vegetarian diet (perhaps for ethical reasons) and still end up eating very unhealthy foods. Merely avoiding animal foods is not the answer to good health. Remember our first dietary principle: choose whole foods over processed foods. Don’t be a junk-food vegan or vegetarian! Yes, studies have shown that vegetarians have a decreased risk of cancer, less obesity, and, depending on the study you look at, possibly greater longevity as well.²¹ We would suggest that those studies track not just decreased consumption of unhealthy animal products, but also an increase in healthy plant-based foods in the diet—greater consumption of fruits and vegetables, whole grains, and beans and other legumes, with all their corresponding healthy nutrients and micronutrients. In the very large European Prospective Investigation into Cancer and Nutrition (or EPIC) study, four combined lifestyle behaviors were associated with an extra fourteen years of longevity—not smoking, only moderate consumption of alcohol, physical activity, and the consumption of at least five servings of fruits and vegetables every day.²²

Becoming a vegetarian should never be considered a ticket to health all by itself. Doughnuts, French fries, and banana splits are all vegetarian, and not one of them is going to make a top-ten health food list any time soon. A whole foods, plant-based diet stays away from refined grains, highly processed carbohydrates and sugars, and oils. In fact, there have even been studies, like the aforementioned EPIC study, that did not find a significant difference in life expectancy between meat-eaters and vegetarians. But here’s a key to interpreting that data: the vegetarians in the EPIC study were eating only half the fiber of the Adventist vegetarians in Loma Linda. That means they were eating far fewer whole plant foods! The Loma Linda vegetarians were eating many more whole foods and plants, and all the healthy fiber and nutrients that they are packaged in. The results speak for themselves—an ordinary population, genetically diverse, with extraordinary health outcomes. As Garth Davis, MD, puts it, “If everyone ate like a Seventh-day Adventist, everyone would have the health of a Seventh-day Adventist.”23

One person who certainly appears to have the health of a Seventh-day Adventist—or of the rural Chinese he studied—is T. Colin Campbell. Today, in his eighties and still robust and active, he runs a nutritional center, teaches at Cornell, and lectures around the world on the benefits of the whole foods, plant-based diet. Visit his offices in Ithaca, New York, and you can stop for lunch at the famous Moosewood Restaurant across the street—one of the country’s original vegetarian outposts. Founded back when not eating animals was considered radical, this venerable establishment has no doubt contributed to Ithaca’s reputation as a bastion of unconventional ideas—“ten square miles surrounded by reality,” as the locals like to say. “Reality,” in America’s food landscape, may indeed still be Big Macs, bologna, and bacon cheeseburgers. Meat is still “what’s for dinner,” more often than not. But thanks to people like Campbell and research like The China Study and the Adventist Health Studies, that reality is shifting. Cultural change can seem slow at times, especially for those who most vividly see a better future, but already the plant-based food movement is strong and growing, and without question it owes a lot to this independent-minded elder statesman.

WHOLE FOODIE TAKEAWAYS

• Eat mostly plants—The correlation between diets heavy in animal foods and higher rates of chronic disease has been well established by large epidemiological studies like The China Study and the Adventist Health Studies.

• Nutritional science needs to be holistic—Many different forms of research add up to a more comprehensive picture. Approach nutritional science with a skeptical mind and look for patterns, not sensational headlines.

• The longest-lived population in the world eats a primarily plant-based diet—If you want to live well into your nineties, eat like an Adventist!

CHAPTER 3

Connecting Diet and Disease

Nutritional Science Looks at the Big Picture

Varieties of Nutritional Science

Challenging American Dietary Dogma: The China Study

WHOLE FOODIE HERO

WHOLE FOODIE HERO

Fiber Is Your Friend

“The Healthiest People in the World”

Five Tips for Digesting Nutritional Science

Vegan Doesn’t Necessarily Mean Healthy

WHOLE FOODIE TAKEAWAYS