The Vegan Mythbusting series uses science to debunk propaganda against veganism.
A long time ago in a cave far, far away, Urt the Prehistoric was dealing with all sorts of predicaments. For one, he had lice in his beard and razor blades had not been invented yet. He had accidentally clubbed his face while trying to kill … of all things, a pesky housefly, even though he didn’t live in a house. His shoes were made from the same stuff as his shirt. But most of all, his biggest problem was food. Thankfully, Urt had a bigger brain that gave him lots of new ideas. So he chipped off some flint to make a blade, used that to trim his hair, then tied it to a pole to make a spear and set off in search a woolly mammoth. He then dragged the carcass back to his cave, and feasted with Mrs. Urt, Urt Jr., Urt Jr. and Urt Jr., and the little lice ate what was left. The End.
Movies and popular culture portray prehistoric people as little more than hairy-faced gruff-looking men who hunted with crude spears and lived in caves. In reality, archaeology is a notoriously complex science because human beings are notoriously sophisticated, and are difficult to study after they’re dead. The sciences of paleontology and archaeology are the setting for bitter debates and legendary feuds between scientists – primarily because it’s so hard to understand how human or non-human animal behaved. I mean, until recently, we didn’t even know that dinosaurs had feathers. And you’ve probably looked at all that classical art and thought that ancient Greeks and Romans had a thing for white marble sculptures. You could look at a rock and know how old it is, what terrain it was in, and even what the atmosphere was like back then. But unlike rocks, living animals have complex emotions, cultures and patterns of behavior that cannot be seen in fossilized bones or cave paintings. And human evolution – that place where archeology and paleontology meet – is the setting for some of our biggest gaps in understanding. That’s why, a lot of times, we have to rely on intelligent guesses and vivid imagination to piece together a picture of prehistoric people.
Okay, so let’s start with what we do know. Among the earliest hominids known to consume meat was Australopithecus. Australopithecus had evolved at a time when forests in east Africa were giving way to grasslands, which had something to do with the fact that they could walk comfortably on two legs. So it’s ironical that the recognition of walking erect goes to another ape who came nearly 2 million years later – the hilariously-named Homo Erectus. H.E. is usually thought of as our ancestor, but scientists aren’t really sure if it was. H.E. likely originated in East Africa, and maybe in Eurasia, but the important point is that between 2 to 1 million years ago, they were calling all of East Africa, the Balkans, India, China, Vietnam and Indonesia as their home. Isn’t that something?
The awesome thing about H.E. was that they made tools by chipping stone on stone. They made crude knives that let them cut hide to get to the meat and the bone to get to marrow. How clever is that? At the risk of offending the sleeping ghosts of my probable ancestors … it’s not that clever. Chimpanzees build sophisticated tools all the time. As do gorillas and orangutans when they really need to. Capuchin monkeys have been recorded drying wild fruit for a week (so that they shrink), then placing them in special depressions (so that they don’t roll away) and pounding them with large stones to get to the nut inside. Crows build tools, Woodpecker finches make them from cacti thorns, and even fish use tools, cultivate gardens and construct shelters. So yes, chipping stones to make crude alternatives to fangs and claws was smart, but not uniquely smart. H.E.’s did not build throwing spears. They didn’t invent bows and arrows. This little fact will get pretty important later in this story.
The other awesome thing that H.E. did was to use fire. It probably took more than 1 million years to master fire, because the earliest evidence for the use of fire is that around 790,000 years old. Why is it important that H.E. knew how to manipulate fire? Because a lot of people incorrectly believe that fire is a human invention. A lot of people think that fire was invented by our species, who came into existence fairly recently, and that it was probably invented to keep them warm during the Ice Age. In fact, the mastery of fire happened around 700,000 years earlier than a lot of people believe, back when our species did not even exist. This is an important fact because people incorrectly think that fire was invented after “humans” got our “big brain”.
But how important was cooking to our ancestors? Well, ask a random person what the most important prehistoric invention was, and they’ll probably chime, “The wheel!” But, notwithstanding with our odd obsession with wheels and sliced bread, it’s perfectly possible to organize a sophisticated civilization, build empires, do conquests, study math and astronomy and build cities without using wheels. Or sliced bread. Hey, the Incas did it. As did the Mayans. Sure, they were conquered by Spaniards ultimately, but they did play a practical joke on all of us in 2012, so there’s that. And they did it without wheels or bread. But, but, but – they did cook their food before eating it. Cooking is not something that only ‘civilized’ societies do, either. Go to the Kalahari and spend a day with the San, who hunt antelope by chasing it under the hot sun for as long as eight hours. They haven’t got longbows and they don’t use wheels, but they cook their food. Travel to the Pamir and Hindukush mountains where tribes keep goats and sheep for fermenting milk, and get most of their annual plant supplies in a few short weeks of summer. They too cook their food. There are tribes in the Amazon who had never had any contact with the rest of the world, but they also cook their food before eating it. You could travel the length and breadth of the world, meet people who live in houseboats on lakes, in tents on Steppes, in treehouses in rainforests, in sweltering deserts and in the frigid Arctic – be it vegan Buddhist monks in Tibet or the Inuit who eat almost nothing but blubber and flesh – they all, without exception, cook their food.
So why is cooking practiced in every culture and every level of civilization? Before we get to that, let me briefly explain something called the Expensive Tissue Hypothesis. Despite its intimidating name, the ETH is a rather simple concept: the amount of calories an organism gets are limited, so for one body organ to grow, another must be compromised. Now, compared to other modern apes, our species has a pretty spectacular brain. A gorilla’s brain uses 8% of his body’s energy while he’s asleep. For a human, it’s a whopping 20%. Some scientists believe that to compensate, gorillas dream in 8-bit, and their favorite dream is Doki Doki Donkey Kong (just kidding). Now, to allow for such a calorie hog lodged in our craniums (expensive but mostly unused, like a sports car), another body part (or parts) must shrink or turn vestigial so that the body saves enough calories to feed the brain. Some body parts cannot miniaturize – for instance, the heart must be a specific size to pump enough blood, and your lungs must have a certain minimum surface area to let you ascend a flight of stairs without passing out (but you take the escalator anyway. Natural selection fails again).
We’ve accomplished this by shrinking our alimentary canal. Relative to other apes, the human digestive system stands unique in how our large intestine is, well, small. In a chimpanzee, for instance, the large intestine is 46% of the entire alimentary canal. For a human, it’s only half as long – around 25%. The large intestine is important, because that’s where complex carbohydrates are broken down. Relatively ‘light’ foods such as fruit smoothies are mostly absorbed in the small intestine, but the large intestine does the bulk of breaking down complex, tough plant tissues, particularly cellulose, which most plants are made of. So the longer the large intestine, the better the breakdown and absorption of food. A longer large intestine can release more calories from a tummyful of food. Cellulose is so tough to break down that even specialized herbivores such as grass-eating cows and deer cannot digest it by themselves – they have to rely on colonies of gut bacteria to break it down for them.
This is where cooking helps. Cooking does part of the work of the large intestine, using heat to break down cellular walls, soften plant tissues and neutralize toxins in plants that we never evolved to eat – such as starchy tubers that grow deep underground. This gives us energy in two ways: one, it saves the calories that our body would have burned for digesting all that food raw. Second, it releases more calories from food by sort of ‘predigesting’ it. That’s exactly what fermentation does, except that fermentation uses microorganisms instead of heat. And just as fermentation lets us eat less-than-ideal food like hard, dry grass seeds (such as wheat), cooking lets us eat starches and makes it easier to digest tougher leaves and shoots.
Now, of course raw food is nutritious. I also understand that raw foodists are not entirely against cooking; only against applying excessive heat to food. The principle of raw eating is to maintain its optimum nutrition. Some processing, such as crushing and steaming is fine in raw diets. Yes, raw food is highly nutritious. But cooking releases more calories, is what I am saying. These calories were critically important to our evolutionary ancestors, because that meant that they had to spend less time finding food. They could use this time to socialize, learn, try out new things. It meant that those hominid apes who had smaller guts could also survive lean times. It meant that those with marginally bigger, marginally more calorie-consuming brains could also survive difficult times and pass on their genes, which resulted in offspring with slightly more intelligence and a slight advantage over the rest of the hominid population. Intelligent brains are generally a bad evolutionary strategy because they consume so much of the body’s calorie reserves. That’s why species don’t keep getting more and more intelligent. Cooking meant that our ancestors could afford to become more intelligent without dying out in times of scarcity.
But wait, isn’t that what meat does? Meat is a calorie-rich food, which means that our ancestors could develop bigger brains by eating meat, right? Right? But can meat be eaten safely without cooking? On a regular basis? What about all the risks of eating meat raw – all the parasites that can carve out nice little vacation homes in the human brain and bloodstream – that true carnivores do not get because their bodies have evolved to process carrion? So what cooking did was to not only allow our ancestors to get more energy from plants, and from a greater variety of plants, but also incorporate meat into their diets – effectively allowing them to get by with just about anything they could lay their hands on. Surviving in harsher landscapes, traveling farther, becoming more successful as hunter-gatherers … all this was made possible by the flexibility and disease protection that cooking offered them. This strategy was successful to the point that human brains developed so well – at the expense of gut size – that, unless they are living in a habitat with plenty of fruit trees and tender shoots all year round, humans need to bake, boil or roast to derive sustenance from starches, meats, seeds or anything else that the land provides.
But “if your ancestors did not eat meat, you wouldn’t even be here!” Hah – checkmate, vegans! But to guess what our ancestors ate, we need to look no further than modern-day hunter-gatherers, such as the San of the Kalahari or the Hadza of the Serengeti. The Hadza, for instance, are skilled hunters. They spend all their childhoods and youth learning about wild animals, their behavior, tracking them and learning to use weapons. They use formidable weapons like throwing spears and bows and arrows – something that no gazelle can outrun. And yet, in more than half of their hunts, they return home empty-handed. Remember that part where I mentioned that Homo Erectus did not have bows and arrows? If modern humans, with their big brains and formidable weapons, have such dismal success as hunters, how do you think our evolutionary ancestors fared?
Living in the wild, these highly skilled hunters derive over 70% of their nutrition from plants. And how do they find enough plant nutrition on a grassland? Because they can cook. Cooking lets them eat starches like tubers which, unlike fruit, are available all year round. The Hadza eat tubers. Pygmies dig for yams. The Amazonians eat wild potatoes and manioc. Australia’s Aborigines collect water chestnuts. Tubers are critically important to hunter-gatherers because, unlike fruit, which are often seasonal, and wild animals, which are difficult to hunt, tubers are available all year round. The dependability of tubers as a food source provided proto-humans with a reliable source of nutrition, which made the evolution of our large brain possible. For the brain doesn’t run on proteins and fats, but on sugars. Cooking gelatinizes starch – releasing sugars that gives calories to the body and nourishes the brain. Wherever humans have called home, they have used the power of cooking to turn indigestible food into nutrition.
Except for the Arctic. The Inuit eat a diet of 99% meat and blubber, yes. Where do their brains get glucose from? Our body does something called gluconeogenesis, which turns some proteins and fats into glucose – glucose which the brain needs. That doesn’t mean that meat is fine for the human body. For all the glorification of the Inuit diets that meat lovers do, the fact is that a meat-heavy diet kills them too. There’s something in meat called L-carnitine, which causes plaque in arteries when it’s digested. Which is a long-winded way of saying that eating meat will, without exception, give you artery plaque (unless you’re a mutant or something). There’s also a sugar in meat called Neu5Gc, which our immune systems attack, which can eventually cause cancer. If your body fights something, it’s probably very bad for you. The Inuits not getting much heart disease is a combination of some evolutionary adaptations and their harsh living conditions killing them before meat does. With modern technology helping them cope with the harsh climate, Inuits still have shorter lifespans other Western people. If anything, the ability of the Inuits to live on a diet of meat shows two things: Firstly, that a species can survive on a poor diet, if individuals can live long enough to produce enough offspring before dying. And second, that cooking allows humanity to survive in almost any condition, on any food, no matter how unhealthy. In essence, it is cooking which has defined humanity by letting us live anywhere, on anything. Including meat. It’s not hard to see that it wasn’t meat that helped our ancestors survive, it was the mastery of fire, which let them cook, which in turn allowed them to derive nutrition from whatever the land provided, in every season, on a compact alimentary canal, which in turn afforded them and their descendants a big, calorie-intensive brain.
Primatologist Richard Wrangham has conducted groundbreaking research into human evolution and diet. He conducted an experiment conductive the calorific value of various food combinations. He considered three diets: one of nuts, berries and raw tubers, the second of 60% cooked tubers, and the third of 60% meat. By calculating calorific values in the experiment, he found that the diet of 60% meat and 40% raw nuts, berries and tubers provides 20% more calories than a raw diet. Impressive? But a cooked vegan diet – one of 60% cooked tubers, and 40% raw plants – provides a whopping 43% more calories [Pennisi, 1999]. So a diet of cooked plants (which are somewhat inedible raw) is providing an increment in calories that is more than twice of that provided by meat. Surprising? Don’t expect Beef Magazine to publish this study anytime soon.
It’s not surprising, then, that around the time we find evidence for the use of fire by Homo Erectus, we also find the jaws of hominid apes starting to shrink in size. Sharp, large teeth that characterized Australopithecus begin to make way for smaller, rounded teeth that excel at mashing softer food. In fact, anyone who has seen the jaws of early hominids must be totally ROFL when carnists point to their tiny, blunt canine teeth as anatomical evidence for carnivory.
The inspiration for this essay is an article that I read in Live Science recently, by someone called Christopher Wanjek. Wanjek’s article is based on a Brazilian study of an anemic prehistoric child, which concluded that the child died because he did not eat meat, which the researchers treat as proof that prehistoric people needed meat. The lead researcher further goes on to claim (with all seriousness) that “carnivorous animals are [as a rule] bigger brained than herbivores”. Wanjek’s article was republished by the Washington Post, condescendingly titled “Sorry, vegans: Eating meat and cooking food is how humans got their big brains”. The article used the word “raw” 10 times and “vegan” 9 times – often next to each other. It’s bad enough that the writer muddled up ‘cooking’ with ‘eating meat’. And it’s kind of hilarious that it’s based on flimsy evidence presented by a researcher who claims that carnivores are always bigger-brained (maybe he hasn’t heard of Google?) But frankly, I think that someone who thinks that raw and vegan are the same thing should probably not even be having an opinion on anything vegan-related, let alone be critiquing veganism in the Washington Post. It’s a stark warning to us all that we should examine scientific evidence ourselves, instead of just naively trusting something because it’s published by a “big-name” media company.
The crux of the ‘meat gave us bigger brains’ argument is that meat, being calorie-rich, “freed up” plant foods, rich in sugars, which the brain needs for its functioning. Well, our evolutionary ancestors couldn’t have use meat to free up anything if they don’t cook it first – that is, unless they wanted to die early and painfully, without passing on their genes. It wasn’t meat that provided calories, it was cooking which allowed our ancestors to digest and derive energy from a far wider range of foods than they could have eaten without the use of fire. This in turn let them have bigger brains, in a slow process over a period of countless generations. Having bigger brains allowed our ancestors do develop complex language, express themselves, form deep social and romantic bonds, pass on their knowledge. Better tools, the ability to record knowledge and maintain a bigger brain let them eventually settle down in one place, sustaining themselves with farmed plants, ensuring the food security they needed to prosper and sustain bigger families. And use the surplus to trade, eventually forming cities and specialized professions. More than anything, it was fire that made us and our brains uniquely human.
p.s. As I mentioned at the beginning of this essay, archeology and paleontology is a complex, difficult science, and the views of scientists change regularly as new evidence emerges. Whatever I have written here is based on my understanding of these sciences. I'm sure that some of you might be aware of different evidence or established facts than I have shared here - I welcome criticism or feedback on the information shared here. Constructive criticism of my writing style will also be most welcome. Is this essay too long? Does it have too many references? Is it too abstruse or simplistic? Your feedback will be valued and taken in the right spirit. Thanks for reading!