Homo Sapiens Are Supposed to Eat What? – Part 1

Darwin P. Kelsey, Executive Director

I’m pretty sure humans – especially American humans – shouldn’t be eating a lot of the stuff in the so-called “Western Diet” now being consumed by millions of people living in our modern industrialized world. Four of America’s top ten deadly chronic diseases are related to that diet. The causes are complex and somewhat hard to understand – harder still to fix.

But homo sapiens (HS) were around for a long time before we began abusing ourselves with the Western Diet. There is evidence that early on, Mr. & Mrs. HS were doing things that my modern day vegetarian-vegan friends wouldn’t like. For example, archeological sites linking humans and charred animal bones date back at least a half million years. At some point – archeologists and others say about 10,000 years ago – many HS types began switching from hunter-gatherers to herder-farmers. And over the last couple of centuries, lots of HS cadavers have been carved open for careful examination of their digestive tracts. It turns out that like rats, pigs, and chickens, humans evolved as “omnivores” – eaters of both plants and animals. More on that shortly.

But first, I have to explain what got me started on this subject just now – or, more accurately, blogging about it (a modern habit I have been resisting). Last Fall, I drafted a “foundation document” to help guide planning and development of a Countryside Center – a new administrative and programming hub for the Countryside Initiative here in Cuyahoga Valley National Park. It included things about the origins and purpose of both CVNP and the Countryside Conservancy (CC) that caused staff members to say “I didn’t know that”. Then they said, “You should share that on our blog.” I said, OK. Then they said, “what about all those books you are always reading and talking about – you should be sharing that stuff on our blog, too”. Uh, OK.

Actually, I began to feel better about this blogging thing when it occurred to me that it could be a little like the column I used to write for the Lake Farmpark Almanac when I worked at Farmpark in the 1990’s. Those short articles were intended to get people interested in and reflecting on some ideas and issues important to their lives, not to mention the planet in general. Some of the things I wrote about then are just as relevant today. So, I am going to begin this particular “blog series” which I’ll call “Homo Sapiens Are Supposed to Eat What?” by sharing a column I wrote for the Lake Farmpark Almanac (Summer, 1999), Vol. 5, No. 3. It was called “Ice Cream for Omnivores” – and it introduced three other articles on the history of ice cream and ice cream making. Most of what I said fourteen years ago remains valid today – and I think interesting. As you’ll see, it does raise issues about what kind of animals HS are, and how their food choices can affect the ecological, social, and economic health of their communities.

Homo sapiens only recently evolved as a consumer of ice cream – the luscious stuff featured in this issue of Farmpark Almanac. Perhaps evolved is the wrong term for the process by which we acquired the habit of consuming vast quantities of frozen and flavored milk. As the following article on ice cream history reveals, the habit was acquired recently, suddenly, and is now just a little shy of universal. In a few countries, such as China, where a “milk culture” is lacking, ice cream remains something of a delicacy. But in western countries such as the USA, an average family consumes ice cream daily. And I don’t blame them.

But lusting after ice cream raises the contentious issue of animal products in the human diet – and that inexorably sucks us into profound questions about human nature. Peter Cheeke ponders this controversy in his recent book Contemporary Issues in Animal Agriculture (1999). He weaves a diverse array of scientific and cultural information into a balanced, fair, and good-humored account. Cheeke possesses a rare gift for putting things in context and perspective. What follows here is based on a small section of his book called, “What Kind of Animal Are We?”

The dietary habits of all animals are strongly related to taste reception, teeth, and digestive tract. Cows, for example, like to eat grass. They have teeth well adapted to grazing and mastication. And they have an enlarged digestive tract, housing a huge population of microbes that digest grass. Fortunately, cows do not like to eat animal flesh, because they lack long sharp teeth, claws, and the speed and stealth necessary to stalk and kill prey. And their digestive tract is not adapted to digesting meat. One might infer, therefore, that cows are herbivores (eaters of plants only) rather than carnivores (eaters of meat only). By the same logic, we can infer that a tiger is a carnivore and not an herbivore. So are pussycats, despite efforts by many owners to feed their kitties anything but meat.

The dietary habits of human animals are also closely related to taste preference, dentition (teeth type), and the way our digestive tract works. It turns out that we are neither herbivores or carnivores. Like rats, pigs, and chickens, humans are omnivores (eaters of both plant and animal matter). We prefer, and are well adapted to nutrient rich, low-fiber stuff like seeds, nuts, fruit, and meat. If you doubt this, try a hearty meal of grass, corn stalks, or oat hulls. Then wait a few hours for additional sensations from the other end of your digestive tract. Should a passing cow ask “was that as good for you, as it was for me?” I think you’ll know the answer.

Some scientists argue that humans must have evolved on a high-fiber, low-fat diet much like our cousin, the gorilla, who finds a vegetarian fare yummy and healthy. They note that captive gorillas, fed diets containing meat and eggs, develop high cholesterol levels and premature cardiovascular disease. Sounds familiar, doesn’t it? Well, our ancient ancestors really did like high-energy, low fiber foods but they didn’t have access to the massive doses of concentrated sugars and fats we consume daily. Nor were they plagued with the sedentary lifestyle, common to modern humans and captive gorillas. Modern humans and captive gorillas simply have not had time to evolve complete tolerance for the potent stuff we pour into our pie-holes.

So – should we or shouldn’t we eat lots of animal products? For starters, it is no longer possible for those of us who hanker after steak and ice cream to claim they are nutritionally essential. Since 1948, when vitamin B12 was identified as the “animal protein factor,” it has been possible for non-ruminants like pigs, chickens, and humans to get along without eating anything animal. Millions of healthy vegetarians – not to mention our modern swine and poultry industries – are proof enough. By using synthetic vitamin B12, we can now satisfy the basic nutritional requirement our bodies have been satisfying for millions of years with animal parts and products. But should we? Do we really need to?

Some people believe it is morally wrong to hunt or raise animals for food. That ethical question can be debated endlessly without arriving at one single right answer. Like the issues of abortion, pacifism, or environmental pollution, the issue of eating meat is complex and value laden. Some say slaughtering a hog is murder. Others say such an idea is irrational, that animals are part of the food chain. Some must live and die, so others can eat. In a normal ecosystem, they note, no wild rabbit ever dies of old age.

What about the global ecosystem? What are the roles of plants? What are the roles of animals – herbivores, carnivores, and omnivores? The answers to these questions are also value laden – ultimately, perhaps, matters of opinion. Like Peter Cheeke, I think herbivores such as rabbits, voles, and deer convert vegetation to a more nutritious form for animals further up the food chain – animals such as hawks, eagles, bobcats, and wolves. Indeed, many kinds of vegetation need herbivores to survive. And many carnivores and omnivores still need herbivores to survive. Domesticated herbivores – like cattle, sheep, and goats – are essentially prey for humans and play an ecological role once filled by herds of bison, elk, and deer. They also make possible “milk culture” – and ice cream. So, think about that the next time you order two scoops of triple fudge chocolate.

Well, I hope this gets a conversation started among Countryside related HS on what we should eat and why – and what that’s got to do with the countryside. In my next blog on this topic I want to “ruminate” on stomachs and guts – how yours and mine work differently than cows’, and how theirs work differently than horses’. I’m not sure which came first, the chicken or the egg – but I know HS guts came along long before the Western Diet; and the two of them are definitely having trouble getting along.


3 thoughts on “Homo Sapiens Are Supposed to Eat What? – Part 1

  1. Comparing us to primates is like comparing apples to oranges. Gorillas and other primates can eat vegetarian only because of the massive colony of bacteria that exists in their extensive colon, which ferments the vegetable fiber to convert it into energy. Humans by comparison has a small colon. Most fiber just passes right through us.

    I strongly recommend this 2-part introduction to exploring the “optimal diet” for humans. If you read only one part, read the 2nd.


    • Brian T. – Thanks for your comment and link to Denise Minger’s two part blog about “What is the Optimal Diet for Humans?” She does a good job summarizing much of the debate about “human” versus other diets. I thought her summary of research regarding the similarities and differences between the digestive systems of humans and other primates was quite good. She makes it clear/understandable how humans’ small intestines and colons differ from other primates – and hence how our diets and theirs can/should differ. They can digest large quantities and types of vegetative matter we can’t – and we can utilize energy dense fruits, animal products, as well as processed/cooked foods they can’t. In short, we are humans and gorillas – not gormans or humarillas.

      Part 1 of my blog on “Homo Sapiens Are Supposed to Eat What?” (originally written in 1999) tried to locate humans (with a bit of humor) on the herbivore, carnivore, omnivore spectrum – for general readers somewhat interested in farming and agriculture. Part 2, scheduled for June (and also originally written in 1999) actually parallels Denise Minger’s description of digestive systems. I tried to describe the three kinds of digestive systems (gut types) – simple non-ruminants, ruminants, and non-ruminant herbivores. According to this classification system humans are simple non-ruminants, and gorillas are non-ruminant herbivores. Non-ruminant herbivores have only one stomach, but they also have very large colons which serve as “giant vats” when millions of microbes ferment types and volumes of plant material that ruminants and simple non-ruminants can’t digest. In fact, they are often called hind gut fermentors.

  2. Evolution doesn’t create “optimum” diets for any species- Homo sapiens, Gorilla gorilla, or otherwise. We are a cosmopolitan species adapted to a variety of environments- and have been for over 200,000 years.

    Evolution works as a series of compromises. Walking on two legs has its drawbacks: We choke more often, have a harder time birthing full-term infants, and have to have knee-replacement surgeries. But, the only thing evolution cares about is whether or not our ancestors who stood on two legs had more babies than those who didn’t. Similarly, evolution only cares about diet if it leads to more babies. Usually, the way to increase the overall number of offspring a female primate has (and yes- humans are primates) is to decrease the amount of time in between births. The way to do that is to increase the amount of fat and sugar in the diet. Evolution doesn’t care that once you hit your postreproductive years you’ll have scores of health consequences, because you’ve already done your evolutionary duty and had more babies than your cousin, who stuck to eating fibrous leaves.

    So, as someone who studies human evolution for a living, I think it can be dangerous to confuse what humans evolved to do (as if there is one singular ancestral diet) with what is healthiest for us now (again, as if there is one solution). By all means, let’s be inspired by our evolutionary history, but not constrained. There should be room in the Homo sapiens diet for decisions based on medical science, a person’s individual history, her genetics and family history, and her own ethical decisions. And let’s not discount personal taste, either!

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