Patrick Eng
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Week 26 - What I Need to Know About Fire's Effect on the Human Diet


In the early days of humanity, ancient humans would consistently carry two things with them as they traveled around the world - language and fire.

While I'm sure my anthropology professor, professor Klauss, would be disappointed in me for not remembering all the different time periods for each stage of human evolution (i.e., ardipithecus, australopithecus, homo erectus, habilis, neanderthalensis, etc), I do remember his explanation of fire's impact on human life.

And like Darwin, he also believed that fire was necessary to make humans the way we are today. It's the very same reason why you won't find any ancient tribes of humans that survived without the use of fire.

On a very basic level, humans are the way they are because of language, culture, and intellect (and every subset in between). But how did we create all these things?

Well, it really depended on the development of a single organ - the brain.

When humans began to cook their food, they unknowingly began to supercharge the food they were consuming. Cooked food gave them more energy to work with, more efficient ways to eat it, and a better way to digest it all. Without the added calories and energy given by cooked food, our brains would not have had the necessary energy budget to grow into what it is today.

Here's why - our brains today use about 20% of our body's energy stores. If your body doesn't have a big battery to work with, your brain isn't going to grow.

Harvard biologist Richard Wrangham has a pretty clear opinion of food's importance though and has put himself through the crucible to test it - like adopting the diet of primates (Warburgia fruit, raw meat wrapped in leaves, etc). His take is simple - life is unfair and diets affect people differently. The issue though is that humans evolved because of and to continue eating cooked food.

Even if you're stuffing your body with raw food, meat or otherwise, you could still starve to death. Do not try this at home. And for all your friends out there who like their chicken medium rare, tell them that besides the obvious stupidity of that, that they are also making themselves dumber for it (but I guess that part should have already been pretty obvious too).

Another Harvard professor, Rachel Carmody, put this idea to the test though to see what was actually happening. She found that when animals were given cooked oat/wheat/potato starch, they received an almost 30% increase in energy levels, and when given cooked eggs, received almost 80% more protein.

For all you businessmen and women out there, think of cooking as outsourcing. Instead of making your digestive system do a ton of inefficient work (in-house), you outsource a lot of the heavy lifting to a different company, like the frying pan. And when the food finally comes down the pipeline into your team's hands, it's easier to work with.

On a cellular level, cooking breaks down the connective tissue in meat (collagen) and makes it easier to chew and digest. With plants, it softens the cell walls and releases the stored fat and starch. All of this was to make eating easier, more time efficient, and healthier. This is especially critical when you realize that great apes spend almost ⅓ of their day just chewing food.

I actually think Jungle Book hit on something very scientific when Shere Khan chases Mowgli due to his alleged knowledge of making fire. Humans are so closely tied with fire, that we wouldn't be here today without it (see also the story of Prometheus and the importance of fire to the human race).

At the end of the day, scientists are finding that cooked find, with the exception of raw fruit, seems to be the preference to most mammals if available. Not only does it taste and smell better, it also provides our bodies with the necessary energy to grow our brains.

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I distinctly remember two things when I took my Anthropology class a few years ago with Dr. Klauss:

  1. Farming was the biggest mistake in human history

  2. Hunter-gatherers produce the healthiest humans

Looking back at history, farming/agriculture began over 10,000 years ago. Before then, humans relied on a hunter-gatherer method, where the men went out to hunt the meat, and the women and children foraged for fruits, nuts, and vegetation.

But when farming came into the picture, traditional hunter-gatherers were pushed off their land and forced into more remote areas of the world. Now, there are only handfuls of hunter-gatherers around the world, and that number is slowly declining.

The studies currently being done on these people though are finding that the hunter-gatherer diet is actually extremely healthy. In short, these people "didn’t develop high blood pressure, atherosclerosis, or cardiovascular disease." Hence our current obsessions with the caveman or paleo diets. The idea is to eat lots of lean meats and fish, but not any dairy products, beans or cereal grains (the sins of agriculture if you will).

But this brings us again to the importance of meat in human evolution. While eating meat is nothing new to humans, eating cooked meat is. Only through the biological changes that cooked meat goes through is our brain able to grow into what it is today.

But, enter stage right agriculture, and all of sudden we get humans who are having babies every 2.5 years (instead of 3.5), a nutritionally static diet, creation of cavities, increase periodontal disease, parasites, and other infectious diseases.

For those who have never gone hunting though, including myself, know that you aren't always able to bring back a kill every time you go out. Almost half the time hunters go out, they actually don't come back with anything. Meaning, the gatherer part of the hunter-gatherer diet is extremely important. These fallback foods actually make up a majority of the hunter-gatherer diet. While meat is still consumed, it is not a daily item on the menu.

Yes, meat was important for human evolution (and still is), but plants made up a large portion of our diet. And anyone who believes that humans are not still evolving might want to read this. Let's use lactose intolerance as an example, a common issue in many Asian cultures. Babies normally have the lactase enzyme, which they use to help break down their mother's milk. But as they get older, they stop producing that enzyme. Countries that began to domesticate cattle though and rely upon dairy products adapted to their new diet and continued to produce that enzyme as adults. But countries that didn't rely on their dairy products had no need to continue producing that enzyme, hence lactose intolerance.

Humans have always adapted to their environment, meaning their bodies will change according to the food around them. The body wants to survive, so over time, it will figure out what needs to change in order to really break down the food that it is taking in.

Cue the Western diet though, full of sugar and fat, and you get populations riddled with obesity, cardiovascular disease, diabetes, and more. When most of us sit at desks for 10+ hours a day, having a diet rich in red meat and fatty foods only shortens your lifespan (also assuming you don't exercise an hour a day). When it comes to the caveman diet, there is no one answer. Your diet needs to reflect what your ancestors ate, not what the internet is telling you.

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Humanity's relationship with fire is believed to have been developed over various stages and over thousands to millions of years.

In the first stage, humans (possible australopithecines at this point) were able to safely interact with fire. Meaning, they were not running away from it in fear.

In the second stage, humans are now controlling and keeping it alive. While they can't make it at this stage and rely upon natural occurrences to make their fire,  they were able to work with it.

Finally, we come to humans that are able to actually create fire. The biggest evidence we have of this is the charred remains we find inside closed settings, i.e., places where fires wouldn't occur naturally. There doesn't seem to be a clear answer as to when this first began though.

In this article, the research team focused on two popular Neanderthals campsites -  Pech de l’Azé IV and Roc de Marsal. Researchers found very explicit evidence of fire usage in the form of ash and charcoal layers. The strange part about all this evidence though was that the fire usage was found to be only used in the warmer eras of history, and absent during the cold ages.

Most people would assume that if humans had the ability to make fire, the best time to do it would be during the winter months. But if that isn't the case, the best we can assume is that at this point, humans still couldn't make fire, and relied upon natural occurrences in the warmer times. And if they didn't have fire during these colder times, did Neanderthals know how to make clothing, or were they just really hairy? Unfortunately, we'll never know for certain. What we do know though is that our interaction with fire and utilization of it didn't happen in a short period of time. It could easily have spanned hundreds of thousands of years, from when we stopped fearing it to actually cooking with it.

In the end, though, we were able to survive without it for lifetimes, even in the harshest conditions. We just aren't sure how.

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Too Long; Didn't Read

When exactly humans began to utilize fire is still a mystery. Sure, we know how long humans have been using fire, but when they began to go from using it only because a tree I was standing next to was just struck by lightning to actually creating their own, that remains a mystery.

Regardless of what exactly happened, though, fire is what made humans what we are today. Only because of fire, and the cooked food brought about by it were humans able to develop brains into the powerhouse organ of the body (like a larger mitochondria if you will). The added calories and nutrients absorbed by our bodies through cooked food allowed us to divert energy and resources away from the regular processing of food to developing of more sophisticated organs.

But this doesn't mean that we should just go to Outback and eat steak to our heart's content. This diet of cooked food, not always meat, was contingent upon a hunter-gatherer diet. This caveman diet relies on food items that were consumed before agriculture was invented - or as my anthropology professor put it, the biggest mistake in human history. As soon as we started farming, we reduced the diversity of our diet, moved into cities, and created diseases that were never known until then.

Even if you started your caveman diet though, did you think about which one you chose? Genetics play a massive role in how you actually process your food, and your diet should reflect that. I don't know how many times I've heard how "everyone's body is different, so a diet that works for one person won't necessarily work for someone else."

Sure, I'm sick of hearing that, but it's true. Asians are more likely to be lactose intolerant than Europeans. Why? Because many Asians stop drinking milk after they get older, while many European farmers rely upon the produce of their cattle for food and money. Therefore, the enzyme that is used to break down milk is only present in Asians while they are babies since they only drink milk at that point in their life. Can confirm as almost my entire family is Asian.

I'd say this is just a gross generalization, but it's backed by science. Whatever the hell that's worth at this point.

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Patrick Eng