While Vegan covers a broad range of lifestyle choices, it is as a diet for which it is mostly known.
Human diet is a thorny and diverse subject. Diverse, because of all species, plant or animal, we have the most diverse diet of any, if it moves, if it doesn’t, we will eat it, or at least try to. Thorny, because many adherents to dietary regimes, particularly in the last few decades, are staunch advocates of their choices citing any research that supports their position, and ignore that which doesn’t.
In the last century we have seen the cost of food for an average working family go from about 80% of their weekly budget to under 20% (source: A History of the World in Seven Cheap Things).
Not only has the cost of food dramatically fallen, but the variety of available food to practically anyone living in the industrialised world, is extraordinary. Not so long ago food, in its variety and freshness would only have been available to the wealthiest, and even then, no amount of money could have bought fresh mangoes to Victorian England!
An increasing industrialisation of agriculture, the scales of mono-cultural farming, the efficiency of transport, the packaging and managing of food have all contributed to this extraordinary revolution, the “green revolution”. No longer is human diet constrained by what is only available by season and locality. It is now quite easy to have organic, sustainable, luxury food anywhere in the world: fresh seafood from Tasmania or New Zealand to the plates of diners in Tokyo with 24 hours? Easy. It is the industrialisation of production, the huge economies of scale, that have made food cheap, plentiful (to the extent that the US discards somewhere around 25% of the food it produces), and accessible.
In the not-so-distant past, most people’s diets were determined by the economies within which they lived. Without refrigeration, food distribution was limited to a small geographical range, and preservation techniques such as salting were the norm. Nutrition values were poorly understood, and given the dictates of geography largely irrelevant anyway, as economics and locality were the primary determining factors of what people did, or could, eat.
The great apes (gorilla, chimpanzee, bonobo, orangutang) all live within a narrow ecological niche; tropical jungles. Their diets are largely fruit based, with some animal products. Human ancestors, as distinct from apes, split from chimpanzees (our closest ape ancestor) sometime between 5-7 million years ago.
It is now thought that human ancestors began eating meat around 2.6 million years ago, primarily because, as every predator knows, if you are smart enough to eat an animal, you gain more time for “other things” than having to eat. Why? It is far more energy efficient to eat meat than otherwise; how much time to grazers, vegetarian animals eat, compared with carnivores? To understand the amount of time involved, within this time period, both Homo erectus has come and gone and modern humans (Homo sapiens) have emerged. If we see this as generations, rather than years, it is 130,000 generations. As has been outlined many times, the argument that we are mal-adapted to meat eating, that this is somehow an alien, a modern occurrence, is hard to fathom; there is plenty of time for those ancestors of ours who are not adapted to meat eating, would die premature deaths through meat being present in the diet, to have died out and not contributed to the gene pool (even if this was the case, which has not yet been proven).
Early evidence of Homo erectus, the species characterised as the first modern human type exists with remains found in Georgia nearly 2 million years ago. This is an area, a climate that would have required some eating of meat, and use of animal fur and skins for clothing, for humans to have survived the climate, the food sources and energy needs of that place and time. It is one of many migrations of “modern” human migrations out of the origin in Africa, migrations that have never been successful for those of our ape ancestors who have maintained a largely vegan diet.
Our ancestors went beyond our home environment in many migratory waves, eventually colonising every landmass, every climate, with a highly adaptive diet. With migration into colder climates our diet changes, an ability to eat meat and extensively use animal products a necessity for survival. Adventuring out of Africa is not a modern phenomena, or even a strictly modern human phenomena with evidence of these early human species found in Europe, in cold climates.
Modern humans are thought to have diverged from our ancestor (Homo erectus) close to 200,000 years ago – a rough idea of when we see a “modern human” morphology. The diet of Homo erectus is known to include meat and fish as well as local, seasonal fruit and vegetables, a diet that changed with locality (as groups migrated from region to region) and with climate. Our species has been eating pretty much anything we can get our hands on for many millions of years. It is how we got everywhere.
With the advent of agriculture, a gradual change in human diet became possible. Until then, our diet was determined by what we had around us, a diet that changed as we moved from our origin point in Africa. Our ability to be flexible, omnivorous, is a critical adaption that enabled us to survive in climates and environments otherwise hostile to animals living solely on a tropical fruit diet. Somewhere around 12,000 years ago (though there is some evidence this might even be over 20,000 years ago) we learnt to cultivate, to farm, plants and animals.
It is curious to think that the biology, the genetics of human beings are the same now as they were 200,000 years ago, our brains as capable of intelligence, our physiques of survival and athleticism, our digestive systems to eat whatever we find. Our diet has changed dramatically in the time we have been farming a blink of the eye in the long evolution of our species. Agriculture laid the foundations upon which we produced a surplus of food and materials, enabling human communities to settle in one place and brought the birth of cities, of trade, all generating wealth beyond what was required for subsistence. We also start to eat food that was not only “out of season”, but also “non-local”; to produce a surplus that is useful you have to be able to store the food you make, and to trade, to transport it.
Food now is cheap, almost a trivial cost, it is plentiful, often in obscene proportions, arising from the technologies of the industrialised world and the green revolution. However, approximately one third (about 2 billion) humans alive today are living on a subsistence diet, not that different from our ancestors, a diet that depends on locality, on climate and season. For those who live this kind of diet, whether it is in the altitudes of the Andes, of the Himalayas, the latitudes of the Northern arctic, the tropical and sub-tropical regions of Africa, of India, the temperate regions of China; these are all rural areas, and a Vegan ideology: no eating or use of animals, would be death to all of them, they simple do not have the technologies to manufacture food supplements, clothing and materials that are required for their environments; for this essentially hairless, tropical animal to survive.
In the industrialised societies, with the ready availability of food, we see a growing concern, and even begin to study, nutrition. What should human beings eat? It is only a question we can have rightly, have generally, asked of ourselves after the beginning of the 20th century. We have seen numerous approaches to this problem: some cultural (such as the essentially Vegetarian diet of Hindus), some religious (where various religions ban the consumption of certain food), some traditional (such as the supposed “Paleo” diet that pretends to go back to a diet that was predominately of our Homo erectus, and early sapiens, ancestors), some ideological (Vegan), but with all of these we haven’t had the knowledge and understanding to truly answer this question, and must accept some superstition in our answers.
It is a very complex and still unresolved issue, one that is only recently being explored. It is still not known exactly how much dependency exists between diet and location, lifestyle, exercise, local climate, and so forth, how should and do diets change based on these factors? For every story, every study recommending one thing, another can be found to contradict at least some facet: it is that complex.
Through drawing on many studies, and examining longevity statistics of well-defined social groups, the Mediterranean diet is thought to be the healthiest human diet. It is the most recommended by health professionals, organisations, etc. It is not a formula, or a proscription of what to eat, but rather an observation of eating habits of these people (Greece, Italy, Southern France and Spain). It consists of a high intake of plants and raw foods: fruit and vegetables, nuts, legumes, oils (olive and canola), a moderate intake of fish and poultry, and a low intake of dairy (cheese, yoghurt, etc) and red-meat (source: EUFIC). Its origin, and recommendation comes from looking at these communities of people who live long and healthy lives. Traditional long-lived communities in Japan have similar diets, though different plant materials and less dairy. Essentially these diets have a low, but necessary, presence of animal food, as well as alot of raw, fibre rich foods, and foods that provide a variety of nutrients. It is the classic “balanced diet” that has been promoted for many decades now. The traditional diet also includes a moderate intake of wine (at least a glass a day)!, and if one cannot recommend wine as a necessity, one cannot from this, say it is harmful.
These diets also highlight the use mostly, of locally available and seasonal foods, where the dietary intake changes over the course of the year. It is not so much stable, as adaptive to what is readily available, which of course harkens back to our early habits prior to the introduction of agriculture.
This is probably the single, safest, generalisation we can currently make about a general human diet. It must be said that this cannot (the components of the diet itself) be applied across all environments (altitude, latitude, cold, warm climates, etc), particularly where such a diverse range of foods is not readily obtainable, and all of these factors have a bearing on how much, and what kinds of food we need to eat.
The complexity of this problem, the infancy of our understanding of this, can perhaps best be summarised by looking at the following scenario, a paper that Vegans promote as a complete, incontestable proof of the validity of their diet. The conclusions drawn by T. Colin Campbell from his China study, that animal-based proteins cause cancer, has led to many advocating a vegan diet.
First, it should be stated that a single study in any scientific endeavour is not sufficient to draw “incontrovertible” conclusions. As with any study, whether of atoms or of complex human behaviour, many, repeatable studies and analysis can only justify strong conclusions or assertions. At best a single study only provides a pointer, proposals to be corroborated by further research.
The importance of corroboration, of repeatability cannot be stressed strongly enough. This is as true of the fundamental sciences of physics as that of the extremely complex systems of biological organisms.
The second point is that that studies that suggest or uncover correlations do not establish causality. Knowing that if “a happens when b happens” just serves as a signpost for further investigation, it does not of its own, establish cause and effect. It is only useful to signify further areas of research. A way of dealing with this fragility is to merge many studies, looking at those common elements within those studies, to see if there are general principles, general correlations that can be made. It is from this technique that the recommendation of the Mediterranean diet has emerged, not a Vegan diet.
To get to some specifics: Indian (Hindu) societies, which are largely vegetarian, with a very limited intake of red-meat, have an unrestricted intake of dairy food. They traditionally report some of the lowest rates of cancer. One of the primary proteins that Campbell targets for his condemnation is “casein, a protein found in milk from mammals”, as being “the most significant carcinogen we consume” (source: wikipedia). If that were the case, why haven’t Hindu societies all perished from cancer? Particularly as they are substantially vegetarian (a prerequisite for Campbell’s recommendations anyway), yet much of their protein intake is from dairy food.
To add to the complexity: it should be noted that the cancer rates within Indian populations have increased as their life-expectancy increases; with change of lifestyle and diet considered amongst the causes. To quote: “Very little is known, however, about the role of the Indian diet in causation of cancer or its role, if any, in prevention of cancer, although more attention is being focused on certain aspects of the Indian diet, such as vegetarianism, spices, and food additives.”
It should also be noted, (as wikipedia page and others do) that many of Campbell’s conclusions are disputed: one point being that it is an excess of protein (whether animal or plant derived) that may be the problem in the cases quoted, not specifically its source as animal derived. An interesting side note to this, is that this is also reinforced with the general shape of the Mediterranean diet, which has a moderate presence of protein in the diet, and a strong emphasis on plant foods. However, there is a startling difference here that cannot be ignored.
And what of the Inuit people of the norther arctic regions? Their diet is almost entirely animal based, their climate cold. Until the beginning of the 20th century, the presence of cancer and other malignant disease is thought to be almost non-existent within their native populations. Surely, if animal protein were a causative factor, they would never have survived? They have inhabited these regions for thousands of years, plenty of time to die out. As with the Indian studies, as life-expectancy has increased, so has the presence of malignant diseases. It is thought that dietary changes are a contributing factor, both to their increased longevity as well as the increasing presence of cancer. But, let us emphasise the point here: prior to this, this almost entirely animal-based diet had no significant presence of cancer.
The problem essentially is this: we do not know what causes cancer; and in fact its causes can be multi-faceted: viral, lifestyle, diet, genetic, etc, etc… We don’t know. It could even be that it is a symptom of age: there is some suggestion that many cancers are formed by the age of 20, but only manifest from the age of 50 onwards. It is not established at all yet what those conditions are. Amongst all human populations, there are those who have lived healthy long lives, with diets that contain daily consumptions of meat, of animal-derived food.
Any advocate of a purely Vegan diet, which has no historical population or precedence to begin with, has also to answer this.
To add another note in this complexity: alcohol has long been thought of as a reasonable addition to a healthy diet; it is certainly a general fixture within the diets of many Mediterranean people. And yet, a recent study also suggests that supposedly suggests that any alcohol is damaging to human health, a study that contradicts many previous studies that showed no (or let us say manageable) ill-effects of small to moderate alcoholic intake, particularly of wine (and the fact that many groups of Mediterranean people drink alot of wine, and live long, healthy lives). There is an interesting discussion here of the tendency to mis-characterise these kinds of correlative studies. No doubt recent studies that suggested that caffeine intake (up to 4 cups of coffee or tea a day) are actually beneficial to your health will be contradicted at some point and we will all be going back to feeling guilty about our coffee intake!
In other areas we have found many dietary factors that effect many people, from gluten intolerance (which can include indications that proteins from wheat can contribute to the same extent as dairy proteins to the development of cancers and auto-immune diseases), lactose intolerance, a plethora of food allergies: nuts, MSG, shell-fish, carrots, etc… The list is long, expanding as we learn more about the vast plethora of food we eat, our extraordinary diversity and individual responses to different diets.
We have also seen with the plethora of food now available, a growing number of problems associated with the types of food we eat: cheap, “junk” food, with diseases such as diabetes, heart conditions, high cholesterol, high blood pressure, obesity, and so on and so forth. Truly diets that kill and are rightly considered the diseases of plenty are emerging from excessive intake of processed food, sugar, too-much-meat, and so forth. In most traditional societies the extent of food, and the processed, unhealthy nature of the many foods we have today is non-existent.
Interestingly, the main contributor to our increasing longevity is not diet at all (beyond having “a healthy diet” – whatever that might mean), but is rather modern medicine. Surgery, hygiene, managing infection, antibiotics, vaccines, all have removed the primary factors that have killed us in the past. As Pinker outlines in Enlightenment Now, more of us are living longer, healthier lives than we ever have in all of human history. Infant mortality and life expectancy have dramatically improved as has the quality of our lives as we age. If you think of it like this: a “healthy diet and lifestyle” is all you actually need to survive: modern medicine, clothing, shelter, etc, these all remove the primary risk factors, the things that really will kill you. We have come along way from thinking that the expiation of sin, the casting out of devils, was required to heal a sick person.
We are, for the first time, in the enviable position of beginning to understand truly, objectively, what foods, what lifestyles will give us long, healthy, active lives. As with every thing else, the answers currently are qualified to different body types, different demands on life, different environments, different climates, different work and play activities, stress levels, and so forth. There seems no single proscription that will fit all of us, all the time, and our dietary needs change as we age, as the conditions and demands of our daily lives change. We can extract some general principles: a healthy diet, exercise, managed stress, supportive social life, etc. At the end of the day, human health seems to be a complex interaction of many factors, and is not reducible to simple ideological statements that purport to serve all humanity all the time.
That is not to say that a Vegan diet can not beneficial; substantial eating of plant food is after-all a part of the Mediterranean diet. if you have eaten burgers and fries, American pizza, cokes and beers your entire adult life, having a diet that strictly denies these foods, that adds healthy food, raw, unprocessed is no doubt a good thing (see Bill Clinton’s adoption of Vegan diet!). There are also some suggestions, some individual experience, that some health conditions may benefit significantly by modified diets, whether Vegan or other alternatives. Far be it from me to make, or indeed take, any kind stance on such issues, these must be within the realm of individual choice and responsibility, and will we hope, be the subject of ongoing and detailed research that is as free of ideological and political bias as we can be.
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