A relentless advance; diet and cancer
It has become appallingly obvious that our technology
has exceeded our humanity. —Albert Einstein
Lord, what fools these mortals be! —William Shakespeare,
"A Midsummer Night's Dream," Act 2, scene 2
For more than three billion years, the earth's creatures have battled for survival and reproductive success, each working diligently to exploit their natural ecological niche. Owls have used their night vision to hunt in the darkness. Cheetahs have used their great speed to run down prey. And armies of locusts have periodically descended upon local environments, ravaging crops like a living wildfire.
This is known as "the survival of the fittest," and has been the fundamental principle in nature for more than three thousand million years. But recently, in just the last 100,000 years, a second dynamic emerged. A thousand centuries ago, our ancestors began to develop a different relationship to the environment, a new way of playing the game of life. Instead of confining themselves to the consistent exploitation of a narrow ecological niche, our ancestors began to modify their niche—a strategy never before seen on earth.
The modern human mind is probably about 100,000 years old, an educated guess suggested by the anthropological evidence. Although earlier ancestors used crude tools and fire, something special took place between 100,000 and 50,000 years ago.1-2 In examining the fossil record of this period, we see evidence of a sudden explosion of innovation. New tools, such as fishhooks and nets and pottery, together with cave paintings and jewelry and sculpture, began to appear.
These relics and tools tell us that their makers were beings that pondered both past and future. At about this time there were anatomical changes associated with increasingly sophisticated language ability. Sometime not too long ago, a group of creatures were thinking and talking and doing things that we would recognize as "like us." We should, because they were us. And they possessed a new survival tool: the modern human mind.
Animal behavior is tightly constrained by a genetic heritage which determines what any individual creature can, and will, ever attempt to do. But within this special period in our history, our species would take a "Great Leap Forward" and attack the problems of survival with a new tool and a new strategy. These ancestors were the first to exploit what anthropologist John Tooby and evolutionary psychologist Leda Cosmides have jointly described as "the cognitive niche."3 This means that instead of simply adapting to an environmental niche, our ancestors began to modify the shape of nature using the power of the mind.
One hundred thousand years ago, human beings began to display a greatly increased capacity for culture—the ability to pass on learned information. This capacity to both learn and teach allowed our ancestors to exploit their environment in novel ways. An early human might have spent a lifetime of trial and error in order to identify a single new fact or survival technique. But now, instead of the value of this discovery disappearing with his or her demise, an innovator could pass on such information to all who might listen. As a result, groups of humans could continually improve upon previous survival tools and techniques with successive generations, a possibility unavailable to other species.
Ultimately, our ancestors began to manipulate the environment rather than instinctively accepting it as a given. Early humans began to change the shape of nature, rather than merely react to circumstances. For example, instead of using their hands to grab for fish, they invented fishhooks and harpoons. Instead of hiking for a drink of water each time they were thirsty, they molded mud into jugs for water transport and storage.
This was the development of the human cognitive niche—wherein the mental processes of thinking, learning, and creating became survival tools of profound importance. This was a novel and revolutionary strategy in the book of life. It was to be the first of three revolutions in the human experiment that would result in our domination of life on earth.
Our ancestors eventually discovered how to affix a sharpened blade to a strong stick, thus inventing the spear and harpoon. These and other tools enhanced hunting success, and fueled a steady population expansion. Increasingly sophisticated clothing, mobile shelters, and boats allowed our ancestors to invade new territories, resulting in further population growth. From about 65,000 B.C. to about 8500 B.C., the human population rose from perhaps 10,000 to six million.4 The human ability to discover, learn, and imitate had made significant strides and was just beginning to have major environmental consequences. The Clovis Indians, for example, used their sophisticated hunting techniques to extinguish many of the large mammal species of North America—including the mammoth, elephant, camel, and giant sloth—within just a few centuries after their arrival on the continent.5
In about 8500 B.C., a group of hunter-gatherers in the Middle East made a momentous discovery. Grasping that the seeds of wild crops were associated with their reproduction, they began to see how to cultivate useful plant species. This insight, together with the ability to utilize it, resulted in a successful new way of living. No longer dependent upon nomadic foraging, people began to more aggressively reshape nature in order to exploit their new understanding of one of life's great secrets.
This discovery and the subsequent agricultural revolution resulted in humans increasing the caloric yield from the land more than a hundredfold, allowing for greatly increased population densities. In addition, agriculture proved to be a more efficient method of food production, making it unnecessary for all members of a community to obtain their own food. This meant time for more diverse activities, leading to a division of labor. Before long, there were weavers, artists, chefs, shepherds, butchers, tailors, smiths, warriors, priests, and politicians. In short, the agricultural revolution is the fundamental reason why human society looks as it does today, in stark contrast to the hunter-gatherer lifestyle that was human life for all who lived before 8500 B.C.
From the time of these first experiments with agriculture to the time of Christ, the human population exploded, increasing from about six million to some 150 million in just eight thousand years. Without agriculture, this expansion would not have been possible, as the planet's wildlife could support only ten million hunter-gatherers. By artificially increasing the caloric yield per acre, our population expanded prolifically. This could only have been accomplished by changing the shape of nature.
Beavers have built dams, and birds have built nests, for hundreds of thousands of years. They, too, change the shape of nature. But, prior to the emergence of the modern human mind, no creature had ever changed the landscape so dramatically. The development of agriculture (and the associated animal husbandry) was a second revolution in our relationship to nature and was stunning testimony to the power of the cognitive niche. It was mental power that was essential—information discovered, exploited, and then transmitted by the human mind from one generation to the next.
By the first century A.D., our exploitation of this niche had resulted in an unprecedented biological success. With a worldwide population of more than 150 million and growing, we had become the infestation of planet earth.
Today, we take for granted that we are "different" from other creatures and masters of our world. But it was not always so. There was a time, not long ago in biological terms, when our species was just another struggling competitor in the game of life. Hunger, starvation, and death by predation were commonplace. In that ancient world, before weaponry and long before agriculture, there were only a few humans per square mile. They did not clear forests, foul waters, or slaughter animals at prodigious rates. In short, they lived within their natural ecological niche.
With our advancement into the cognitive niche, this changed. Beginning with efficient hunting and continuing with the manipulation of plant reproduction, our species developed a way of life outside of our natural ecological niche. We came to have artificially high population densities, with our survival dependent upon the manipulation of nature.
Many of the consequences of this change were unappreciated by those who lived through them, because they took place over centuries. Using a longer-term perspective, however, these changes were not only significant, but rapid and extraordinary. They included widespread deforestation, the fouling of rivers, mass extinctions, and the spread of diseases. The large-scale overgrazing of domesticated animals, for example, is the reason that a once-lush area of North Africa is now known as the Sahara Desert.6
Our success allowed us to live in fixed communities and to increase our numbers. But this success had many unforeseen consequences. Epidemic diseases such as malaria and cholera were catastrophic consequences of this artificial new lifestyle. And when humans began to traverse the globe with boats, they transported diseases to virgin environments, with devastating results. As Jared Diamond explains in Guns, Germs, and Steel, far more people have died as a consequence of these activities than have died in the history of human warfare.7
Despite setbacks, however, our ancestors continued to push on. The advantages of the specialization of labor, of living in close proximity, and of aggressive exploitation of nature could not be stopped. The march of history is that of the human race obeying the mantra of the motivational triad—attempting to attain more pleasure, for less pain, with ever-greater efficiency.
From the time of Christ to 1700 A.D., the pace of progress was not fast or biologically lucrative. During those seventeen centuries, the world's population had merely tripled to about 500 million by the time of Isaac Newton. Despite a steadily growing knowledge base, no innovation as significant as agriculture had taken place in some ten thousand years. The population growth was primarily due to agriculture displacing the hunter-gatherer lifestyle. By the 1700s, people lived in societies with structures we would recognize. Most lived within agrarian-based economies, complete with butchers, bakers, candlestick makers, and armies. The world's ecological landscape had changed slowly but significantly across those centuries, with cleared forests, irrigated fields, and cities teeming with humans, their animals, and their wastes.
These changes would soon accelerate. Within a few decades, history would witness the dawn of yet another revolution in our relationship to the environment. This third revolution would be the culmination of the previous two and would result in newfound capabilities. It would make us the masters of the planet, and of all its resources. But it would also make us, and all life on earth, increasingly vulnerable to the limitations of our collective judgment.
In the fable of the Persian Chessboard, the Grand Vizier to a king invented the game we now know as chess. The game was played on a board, with eight columns and eight rows, totaling 64 spaces upon which two rival kingdoms could engage in a game of war. According to legend, the king was so pleased with this invention that he offered the Grand Vizier a reward of his choosing—dancing girls, feasts, even a palace. The Vizier declined, however, asking of the king what seemed a modest reward. He requested a single grain of wheat on the first square of the board, and then a doubling of this on each successive square. Thus, he would ask for two grains of wheat for the second square, four grains for the third, and so forth, until he had the appropriate amount for each square.
The king objected, considering this to be an absurdly modest tribute. But the Grand Vizier insisted, and the king consented. The monarch would soon see, however, that he had made a serious mistake.
By the end of the first row, at the eighth square, the total is 128 grains, a small cupful of wheat. But, by the end of the second row, at the 16th square, the amount is 32,768 grains, about 20 pounds of wheat, and is no longer quite so trivial. By the end of the third row, the amount for the 24th square is 8,388,608 grains—5,120 pounds of wheat, enough to feed a man for 10 years. By the fourth row, just halfway across the board, the amount is over a million pounds of wheat, more than the entire annual wheat production of the ancient kingdom. And by the 64th and final square, the amount is unimaginable, far exceeding the entire world's wheat harvest of the twentieth century.8 The mythic king may have been unable to fulfill his obligation, but he learned a great lesson.
The fable of the Persian Chessboard is often told to illustrate the phenomenon of compound interest and to express the importance and power of long-term investment. With a mere savings of just $400 per month, for example, a 25-year-old worker will be a millionaire by the age of 65, having saved only $192,000, but having earned the remaining $800,000+ in compound interest. Steady investment is indeed a good long-term strategy, if one's goal is fabulous wealth, a pleasant retirement, or paying for your children's education.
But there are investments other than money, and some that can also accumulate and multiply. Knowledge is one such example, and by the 1800s, centuries of investment in human knowledge had culminated in the third great revolution of the human story: the Industrial Revolution.
The ability to learn new things and to pass on knowledge is the fundamental reason for our domination of the earth. This domination had been growing steadily for many centuries, fueled by the bounty of agriculture that made possible the specialization of labor. With each new generation, the collective capital of human knowledge increased, culminating in highly specialized civilizations by the midpoint of the last millennium. This steady but unspectacular growth of knowledge was given a boost by the invention of the printing press, but did not catch fire until a great conceptual leap was achieved.
Beginning in the late European Renaissance, a few brilliant men saw that there were limitations to the normal process of human discovery. A procedure to overcome these limitations was invented—called "science"—that soon became the fountainhead of human progress. Instead of relying on the pedestrian method of trial-and-error, early scientists learned how to systematically identify causal forces in what became known as the scientific method. This procedure would prove to be more efficient than any previous method of discovery.
In the space of just a few hundred years, the scientific method would allow human knowledge to become a Persian Chessboard of increasing understanding. As a result of that increased understanding, humanity would soon gain the capability to bend the shape of nature to its will. This extraordinary historical phenomenon, the wedding of science to technical problems of survival, became known as the Industrial Revolution. By the middle 1800s, the quality of life for those living within the reach of western science was rapidly improving in a process that would eventually become the envy of the world. Just a few thousand years earlier, getting enough to eat required relentless and tenacious effort. But by the late twentieth century, the average American could obtain a tasty meal high in sugar, fat, and salt in exchange for a few minutes' wages without ever setting foot outside of his or her car.
Life on earth is interrelated within what we refer to as "the ecology." This set of complex relationships is never in static balance; it is dynamic, always changing. Though we often refer to "the balance of nature," such a term is somewhat misleading because nature is never in perfect balance.
The ecology is not the result of a well-ordered, well-balanced scheme. It is the result of a brutal, dynamic contest in which those with an upper hand are instinctively driven to exploit every advantage. But there are natural limitations to any upper hand. When a given species becomes particularly effective within an ecological niche, its numbers expand. With this expansion comes increasing competition within that species for limited resources, as well as increased opportunity for predators.
Predator expansion is a natural boundary to the expansion of prey species. If a wildflower suddenly benefits from a change in the weather, an animal that grazes on that flower may become more numerous, only to have its numbers checked by a corresponding population growth of a local carnivorous cat. A dynamic balance, in this rough sense, does exist.
With the human invasion of the cognitive niche, however, our ability to artificially intensify food production has resulted in human population expansion, a biological success unchecked by the normal constraints of food supply and predation. Aided by science and technology, the human population has expanded at an incredible pace. Perhaps 500 million in Newton's day, the world population reached a billion by about 1800, doubling in little more than a century. By 1927, the world population had doubled again, to two billion, taking it to 200 times the carrying capacity of the planet, if humans lived within their natural hunter-gatherer niche. By 1974, less than 50 years later, the population had doubled once again, this time to four billion.9 With this growth came alarming ecological consequences.
By the year 2000, the world population had grown to six billion, a concentration of humanity one thousand times greater than existed at the dawn of agriculture. But more importantly, of that thousandfold growth, half took place within 35 years! A Persian Chessboard of biological success.
This success is the result of human innovation, the consequence of increased understanding in agriculture, medicine, sanitation, and industrial production. No other creature on earth has ever had this degree of success. We have left our ecological niche behind, and now live in an artificial world of our own making.
We no longer forage for plant food, we grow plants treated with pesticides, harvesting them at will. We no longer hunt wild game, we consume animals that live out their lives in feedlots, injected with hormones so that we can get more pleasure for less effort. These animals live in artificially close quarters, eating a contrived food supply, protected from predators. Their artificial population densities leave them susceptible to another natural constraint: predation from microorganisms.
But we have managed this problem, as well. These animals are medicated with antibiotics, so that infectious disease does not ravage these herds as they surely would in nature. More than 90 percent of all antibiotics produced are slated for animal administration.
We no longer drink from pristine rivers, of water naturally distilled as raindrops. We drink water from water treatment plants, from rivers and oceans used as dumping sites for concentrated sewage and industrial waste. And we breathe air not occasionally made impure by a random fire or volcanic eruption, but air that has been systematically assaulted by field burning, power generation, industrial activity, and the internal combustion engine.
The extraordinary success of our species, then, has not come without a price. But, unlike the subtle changes of centuries past, these recent changes have been widely noticed. Today, no educated person can ignore the undesirable consequences of our success. We have indeed successfully reshaped nature, but that reshaping has polluted our home.
By the second half of the twentieth century, the human onslaught to modify nature had reached a feverish pace. Unlike the subtle changes that had taken place in centuries past, people were able to observe firsthand the astonishing rate of human success and both its desirable and undesirable consequences. From a world with just a few automobiles in the early 1900s, a long-lived western observer could not miss an amazing transformation of life and landscape: By the year 2000, there were more than 500 million cars.10
From our viewpoint, there are two primary questions to be faced about the nature of our new relationship to the environment. The first is this: Is our artificial mastery of the earth's resources marching us toward disaster, as we overwhelm the balancing systems of the earth's ecology?
This is a profound question that will require unbiased and careful science to answer in the hope that we may act in time to protect our planet. This question about our changing relationship to the environment often seems too big to ponder, too big to grasp. We can exert influence with our pocketbooks and our votes, but we realize that it may or may not be enough.
But a second question is this: Are the environmental crises we have created—adulterated water and air, chemical contaminants in our food and in our environment, and increased sources of artificial radiation—health threats that are likely to seal our individual fate, regardless of our diet and lifestyle choices?
It is to this personal and important question that we now turn.
The single greatest threat to health within industrialized society is atherosclerotic vascular disease, a condition largely attributable to dietary excess. Together with cigarette smoking, it is the excessive consumption of fat and protein in general, and animal fat and animal protein in particular, that is at the root of most stroke and heart failure. The causes are quite clear. The solutions to avoiding this fate are within our personal control.
But there is another major health threat with causes that seem mysterious. It destroys millions of lives annually. That threat is cancer, a disease that is at once both physically and psychologically devastating. Unlike vascular disease, which has been shown to be reversible through diet and lifestyle choices, cancer is too often a diagnosis without hope.
Cancer is evidence that something has gone very wrong. The fabulous machinery of cell reproduction, meant to last us nine decades or more, has gone awry. Bits of our cell-reproduction machinery, sequences of a given cell's DNA, have become deranged and are dysfunctional. The cell reproduces too quickly, and imprecisely, no longer following the correct reproduction instructions. In a matter of months or years, this imprecision becomes noticeable as a tumor or lesion. Very often, it is fatal. Nearly 25 percent of Americans will die from cancer of the breast, lung, colon, or prostate. Precisely how this happens is still, in part, a mystery.
In the last few decades, much has been learned about this daunting problem. Some cancers are treatable, and modern medicine does indeed perform miracles every day. But, for most cancer patients, modern medicine is still seeking answers to frustrating questions. For most cancers, we simply do not have effective treatment. For example, contrary to irresponsible propaganda, the success rate for breast cancer has not changed in 80 years, though the treatments have become increasingly unpleasant. Despite the escalating aggressiveness of surgery and chemotherapy, women do not live longer post-diagnosis than they did in the 1920s, and more than 90 percent of women diagnosed with breast cancer will die of this disease.* (See endnote, p. 214.)
Rachel Carson was but one victim of this epidemic of despair. In Silent Spring she wrote of her suspicion that the root causes of cancer lay in the pollution of our internal environment as the result of poisoning the external environment. Carson was horrified that the pollution of the planet might be critically connected to an emerging pandemic of cancer and believed that our only hope, collectively, was to radically change our course.11 Her voice has been echoed by more recent critics, such as John Robbins and Howard Lyman.
RISK FACTORS FOR CANCER
Many feel that contracting cancer is like losing the lottery. Whether caused by environmental poisons, genetic flaws, or both, many believe that fate plays an enormous role. We are vaguely alarmed that, for some reason, a growing number of us are very unlucky. The idea that toxins in the air, water, food, and general environment might cause cancer has only contributed to our collective sense of powerlessness. After all, we have no choice but to breathe, and we have to eat something. And although we can pay extra for the privilege of drinking pure distilled water, for many it might seem like too little, too late.
Although our environment is indeed becoming increasingly toxic, this dark cloud has a silver lining. Most fortunately, in their suspicions regarding the root causes of cancer, it appears that Carson and other environmentalists may have been only partially correct. After several decades of scientific investigation, the National Cancer Institute has finally been able to determine what types of stressors are most important in the development of cancer, shown in the table above.12
Cancer, it appears, shares an important characteristic with cardiovascular disease: It has causes that can be largely controlled with diet and lifestyle choices. These choices can determine our odds with respect to cancer, which puts this major threat largely within our personal control.
The degree and nature of our control over cancer is neither well-known, nor well publicized. In the years since the publication of Silent Spring, news reports have created periodic sensations with concerns over a given toxin and its relationship to cancer. Suspected culprits are chemicals such as DDT and other pesticides, Alar (sprayed on apples), Red Dye Number 2, sodium nitrites and nitrates, dioxins, aflatoxin (from moldy peanuts and corn), artificial sweeteners such as saccharin and cyclamates, and industrial pollutants. All of these suspected culprits have been subjected to scientific study, and all have been found to be associated with cancer development. As a result, the public understandably fears that cancer is a grim fate largely determined by one's degree of exposure to minute concentrations of carcinogens, an exposure for which we have no sensory organ to give warning.
The belief that cancer is the result of exposure to carcinogenic toxins is partially correct. But it is extremely misleading. The truth about cancer is more complex, and much more promising. For it appears that the primary culprit in the development of most cancer is observable and controllable: it is the consumption of animal protein. One of the first to grasp this connection was Cornell University biochemist T. Colin Campbell.
As a young nutritional biochemist, T. Colin Campbell was, like many of his colleagues, fascinated with protein. His doctoral dissertation, funded by the Dupont and Grace Chemical companies, was an investigation into how to produce more and better high-quality protein. All over the world, nutritional biochemistry was focused on this and related tasks: how to efficiently and inexpensively produce more animal protein to feed an "undernourished" world. Since its discovery in the early 1800s, protein was the hallowed chemical of the body. For various and assorted historical reasons, proteins from animal sources were viewed as superior to those from vegetable sources. This seemed reasonable and right to the young biochemist who had grown up milking cows on the family farm. After all, Dr. Campbell thought he knew better than almost everyone why protein was so important, and why animal protein was the most important nutrient of all.
As his career blossomed, Campbell became one of the most respected nutritional biochemists in the world. A scientist with a diversity of research interests, Campbell was particularly interested in the connection between toxic chemicals and cancer. As fate would have it, he happened upon an obscure research paper, published in India, reporting on a study in which rats exposed to a Class IA carcinogen (aflatoxin) were fed either a 5 percent protein diet or a 20 percent protein diet. Campbell found himself puzzled by the results, which were completely counterintuitive: Every single rat fed the 20 percent protein diet developed liver cancer or its precursor lesions, whereas not a single animal fed the 5 percent protein diet developed liver cancer or a precursor lesion!
Campbell was uncertain what to make of the study and consulted numerous colleagues. The feedback from his fellow experts was clear: The Indian scientists must have misreported their data and accidentally reversed their results. It was inconceivable—nearly sacrilegious—to a community of nutritional biochemists to suggest that protein could be a culprit in cancer.
But great discoveries are often made by those who refuse to explain away the inconvenient detail, those with the courage and determination to question what "everyone knows." T. Colin Campbell is such an individual, and subsequent studies conducted by Campbell and his colleagues represent some of the most important work ever done in cancer research. The results lead us toward conclusions that threaten personal preferences as well as special interests. Nevertheless, the truths he uncovered are priceless.
In a series of astonishing experiments, Campbell and his colleagues not only confirmed the original results from India, but provided a critically important additional discovery. In one investigation after the next, Campbell and colleagues demonstrated that it is not protein per se that determines cancer development, but that it is animal protein that is the primary culprit.13
Campbell and others have discovered that cancer is being constantly created in the body by various and assorted environmental assaults, primarily through dietary pathways, but also through toxic chemical exposure, including cigarette smoking. However, toxic exposure is often insufficient for the development of cancer. In order to defeat the body's natural defenses against it, cancer must be promoted. Campbell's investigations have shown that animal proteins are by far the most effective promoters of cancer that have been identified. And to his surprise, Campbell has discovered that the primary protein of dairy products—casein—appears to be the most aggressive promoter of all.14
Cancer develops in a three-stage process that involves initiation, promotion, and finally, progression. Initiation is a process of DNA derangement that can take place within minutes of exposure to a toxin. By itself, initiation is not dangerous because we have anticancer machinery that effectively eliminates these cellular mishaps. The most critical part of the process is promotion, in which the fledgling cancer is "fed" and encouraged, a process that takes place across months and years. It is here that animal protein does its damage, leading to the final stage of cancer that we can observe with medical instruments and even the naked eye: progression. By this time, there is usually little to be done, as the cancer is no longer controllable.
Studies in Campbell's laboratory and elsewhere have demonstrated that without animal proteins in the diet, the initiation process of cancer development is often stalled. The evidence points us toward a startling possibility: It appears that, regardless of the level of exposure to the initiating carcinogen, many cancers may be unable to develop and progress without the presence of animal protein in the diet! This finding, both counterintuitive and unpopular, is nevertheless a discovery of incalculable importance. Despite the widespread proliferation of toxic materials in our food and in our environment, we still may maintain a huge degree of personal control over cancer by simply controlling what we put in our mouths.
A dream of cancer research has been to find the cause of cancer and to identify how to prevent it. It is somehow fitting that a nutritional scientist who spent his young years on the family dairy farm, and who subsequently pursued a career in science seeking to discover methods for producing more and cheaper animal proteins, should be confronted with a clue that animal proteins are the greatest threat of all. All that was needed was the determination and courage to discover and to tell the truth.
Is polluted air and water a risk factor for cancer? Yes, this appears to be the case. But this threat is minor when compared to the risks associated with poor dietary choices and cigarette smoking. Are the waxes in milk cartons a possible source of carcinogenic material? Yes, but they are not likely to be nearly as dangerous as the milk within the carton.
And finally, there is one more important bit of good news. Despite widespread publicity about how genes cause cancer, careful scientific study provides a proper perspective. Epidemiological studies conducted by T. Colin Campbell and others have demonstrated that most cancers are attributable to dietary and lifestyle factors. Migration studies, in particular, are extremely convincing. For example, when Asian women migrate to the United States and adopt our dietary practices, they experience increased breast cancer rates of up to 500 percent.15 These findings support the conclusion that diet is the primary causal factor responsible for the strong correlation observed worldwide between dietary habits and cancer incidence.
Diet and Cancer Risk It is fortunate that the very same dietary patterns that promote cardiovascular health serve to minimize cancer risk. A diet of whole natural foods not only promotes the reversal of cardiovascular disease, but also provides the body with a rich and continuous supply of phytochemicals, nutrient-like substances that combat cancer formation. These helpful chemicals are not found within any animal products, and they are not a significant component of processed foods.
In addition, on a calorie-per-calorie basis, plant-based foods contain much lower concentrations of environmental toxins than do animal-based products. This is because of a phenomenon known as "biological concentration," wherein animals act as filters for environmental toxins and concentrate these toxins in their tissues. As a result, their flesh and their milk are thus much more concentrated with such contaminants than the original vegetable-matter source. For example, women who consume animal products have been found to have 70 percent higher concentrations of DDT in their breast milk as compared to vegetarian women.16 While the impact of increased toxicity on the developing child is unclear, we can hardly expect such toxic exposure to be a good thing. It will be left for future researchers to determine the extent and nature of the health compromises resulting from toxic exposure. But in any case, our conclusion is this: We appear to be best protected by minimizing or eliminating all animal products from our diet. And the more toxic our environment becomes, the more importance this prescription will have for all of us, both individually and collectively.
Throughout our planet's history, nature has given birth to an astonishing array of life forms. Across eons of biological time, that history has witnessed the rise and fall of a fabulous diversity of life. Different species have evolved extraordinary survival equipment—including eyesight, sonar, wings, fins, and the neural circuits needed to spin spiders' webs. Many of life's contests have had surprising endings. It is not always the biggest and the strongest that survive and thrive, but the "fittest." At any given moment, the day belongs to those creatures that adapt most effectively to their environments, who "fit" the best—not necessarily those with the biggest muscles or the sharpest teeth. Many great predators have risen only to fall as victims of the ever-changing circumstances in nature's unpredictable theater.
A hundred thousand years ago, a primate began rising to prominence on the African continent. Within a few thousand years, this species would wield a new weapon that would set the stage for a profound twist in the earth's natural history—the modern human mind. One hundred thousand years later, that mind would learn how to make the most of its abilities, inventing science as a method to unlock the mysteries of nature itself. Within just a few hundred years, the results would be incredible, with successes unimaginable to those who lived just a few generations before.
But knowledge can be a two-edged sword, and those successes have not come without a price. Pesticides such as DDT save millions of lives by reducing the incidence of malaria, and this is indeed a blessing. But widespread use of such substances causes damage to the earth's ecology, with consequences that are difficult to evaluate. Just because we can do something doesn't mean we should.
As more of the world's peoples become technologically advanced, they crave more pleasure with less pain and for less effort. This results in an ever-widening assault on the environment, from the razing of rainforests for the production of cattle to the burning of increasing amounts of fossil fuels. Our activities are resulting in mass extinctions, wherein the rate of species lost is perhaps one hundred times the rate prior to the Industrial Revolution. And this rate appears to be accelerating.17
Our desire for animal flesh also results in the ever more sophisticated assault on the earth's final hunting ground: the oceans. We now fish the world's waters with radar and satellites. It is not even close to a fair contest. It should come as little surprise that we have destroyed 90 percent of the population of many marine species in just the past few decades, and we have rendered others extinct. Our cognitive abilities now reign supreme, but we are rapidly laying waste to our own nest. Our collective biomass has become 100 times greater than any large animal species in the history of life on earth.
Even in early days of the Industrial Revolution, many people were worried about our impact on the environment. A literary giant was among those whose voice was heard and respected. Charles Dickens looked out across the landscape of his rapidly changing country, and he spoke of his growing concern. In his novel Hard Times, Dickens wrote of the fictional village of Cokestown, which was in fact the real-life town of Preston in Lancashire. He described it as
…a town of machinery and tall chimneys, out of which interminable serpents of smoke trailed themselves for ever and ever, and never got uncoiled. It had a black canal in it, and a river that ran purple with ill-smelling dye…a town of red brick, or of brick that would have been red if the smoke and ashes had allowed it.18
Dickens was alarmed by the changes that were taking place, changes obvious and rapid. Today, the pace of these changes has skyrocketed. And, more alarmingly, the damage is often being done at the microscopic level, as our biochemical manipulations create problems that make those of nineteenth-century England look trivial by comparison.
In the game of chess, an experienced player may take a novice to the brink of defeat in just three moves. The fourth move can be checkmate, and the kingdom is lost.
Analogously, it has taken three revolutionary developments for us to become masters of our planet. Our modern human mind, together with advancements resulting from the agricultural and industrial revolutions, has created an environment where we can get more pleasure for less effort than any hunter-gatherer ever would have dreamed possible.
But we must now rule with great care. We must, because money, knowledge, and populations are not the only things that may grow geometrically on the Persian chessboard. Environmental destruction is another. As one species is extinguished, so may several others that were ecologically interdependent. If we do not learn to make much better decisions than we have in the past, a grim fate may await our species. The fourth revolution in our relationship to the earth may be worldwide ecological collapse, an environmental checkmate.
Humanity needs help in order to make better decisions, since tempering our desires does not come to us naturally. With luck and guidance, we may yet find the way.
Dickens was a thoughtful critic of the Industrial Revolution. Yet it was another Englishman, Charles Darwin, whose insights still have much to teach us.
Darwin is rightfully revered as the man who explained (to an astonished and often hostile world) where we came from. He explained that we are related to all living things in a single interwoven tree of life. His evolutionary theory was the fundamental insight of the life sciences, and he will be always remembered for this achievement.
But Darwin did more than solve one of life's greatest mysteries. He made two other related discoveries that rival the theory of evolution in terms of practical importance. These two discoveries may together sow the seeds of a fourth and final revolution in our relationship to our environment—one that is urgently needed.
For more than a century after Darwin's publication of The Descent of Man, Darwinian thought would be virtually ignored by the social sciences. Twentieth century scholars in psychology, anthropology, and sociology turned their collective backs on the greatest mind of the nineteenth century, to what has become their collective embarrassment. As the twentieth century came to a close, Darwin's understanding of human psychology began rising to preeminence, led by the scholarship of Richard Dawkins, Edward O. Wilson, Robert Trivers, William Hamilton, Steven Pinker, John Tooby and Leda Cosmides, David Buss, and others.
Finally, we have rediscovered what Darwin had seen clearly more than a century earlier, that we are beings with bodies shaped by nature, with minds designed to match. Our hopes, dreams, desires, and thus ultimately our actions, are derived from evolved mental structures. We pursue pleasure, avoid pain, and conserve energy as guided by these structures.
Our animalistic nature, combined with our burgeoning technological abilities, is propelling us toward potential disaster. We cannot retreat to our natural ecological niche. We can only use our knowledge with greater wisdom by recognizing the dangers of giving free rein to our permanent upper hand.
Executing restraint will be difficult because it conflicts with our nature. So it is a clearer understanding of our own nature that we now need most, and it was Darwin who pointed the way. He founded what has only recently been recognized as the key perspective for social sciences, what we now call "evolutionary psychology." This revolutionary paradigm is currently making social science far more accurate and potentially useful than ever before.
We can only hope that enough knowledge arrives in time, for we are dealing with dangerous affairs. We believe that Darwin would have appreciated our view that the pleasure trap is a hidden force of alarming potency—not only a threat to our individual well-being, but to our collective fate, as well. We will need a fourth revolution that will teach us to respond not like animals, but rather to partake and refrain in a more enlightened manner.
As human societies continue to ravage our planet, we may personally be spared the consequences by controlling our individual behavior. This can be a great comfort, a blessing, a reprieve for the asking. But the fate of future generations is now in the balance. Our planet is awash in the consequences of our material success. It is here that another Darwinian insight becomes vital, its appreciation crucial to the future of life on earth.
It was Darwin who first understood that living things fit together in interdependent ecological niches. It follows, then, that life on earth is like a woven fabric of uncertain elasticity, and that we should be greatly concerned as we stretch that fabric to its limits. Many valiant voices have been raised in defense of our fragile environment, and many more will be needed. But we should remember that it was Charles Darwin who founded the modern science of ecology. And it is to his memory that we pay tribute with our growing awareness that no species is an island unto itself.
Starting 100,000 years ago, humans began to take the first few steps in a novel journey. They began the process of changing the environment to suit their needs, and they left their ecological niche behind. As a result, we have become the masters of the earth's resources. The environmental damage done by our species has been staggering, and the consequences ominous.
One fear has plagued scientists, physicians, and environmentalists: the question of whether our pollution of the environment is responsible for our current epidemic levels of disease, particularly cancer. While the answer to this question is not as yet definitive, some facts are now known. Fortunately, most cancer is unrelated to toxins within our air, water, and general landscape. Far more dangerous is the likelihood that animal protein acts as a catalyst in the promotion of cancer.
Consume a diet of whole natural foods, excluding all meat, fish, fowl, eggs, and dairy products. In addition, utilize organically grown produce whenever possible. Finally, water for both cooking and drinking should be distilled, to reduce unnecessary exposure to toxic substances in municipal water supplies.