What Should Humans Eat?

The subject of what humans should eat has been a long debated topic. Sadly there is a lot of misinformation here. There is a growing voice against eating meat and it is gaining traction. Many people in Hollywood support this and Netflix has several documentaries on the “dangers” of eating meat. Veganism is also gaining a lot of support all over the world. Seems like everyday I see an ad advocating for veganism or plant-based products, touting a processed food over something nature gives you. In addition to this, the concern over the environment has narrowed its focus on cattle and other animals. It is a mounting storm against something that was crucial to human evolution.

But first a word, a good portion of this post will be about evolution. I understand not everyone believes the same things. I will not get into the issues of dating and other controversies. That is not the purpose of this blog or website. This is about optimal health. So if there is an issue with the dates or evolution feel free to think of it as designed and fitting within a short time frame. It doesn’t dispute the fact that our modern diet and lifestyle is radically different from our ancestors, and that this plays a crucial role in why we are sick.

My Journey into the World of Nutrition and Weston Price

I meant to write this article months ago, but I kept delaying it. I have been experimenting with my own diet, trying different things, listening to podcasts and lectures, and studying. Over the years I have spent countless hours studying nutrition and optimal diet. I got interested in nutrition while I was in my associate degree program. It didn’t fully take hold until I started chiropractic school. Like many, I didn’t see the importance. Yes, I knew it was important to eat your veggies and to be careful to not eat so much junk food, the generalities. However, I downplayed it like so many do. But many things didn’t add up. One of which was the growing presence of chronic disease. Something was off, could it be diet related? I soon discovered that diet had a critical role to play in chronic disease.

My family like many others are plagued with chronic disease, but this was not always the case. When I started chiropractic school my sister-in-law told me about a book I should read, Nutrition and Physical Degeneration by Dr. Weston Price. It was published about 100 years ago and it describes the author’s travels. Dr. Price was a dentist who wanted to understand how indigenous cultures faired compared to those who ate the Western diet. The Western diet was not as processed as it is now, but it still included many refined grains and processed foods. What he discovered was many of these cultures had more robust teeth and jawlines with little to no dental caries. He also discovered they had little to no chronic health concerns. As he studied them he noticed when the Western diet was introduced to them that within one generation their teeth, their jaws, their entire bodies were negatively effected within one generation. He took hundreds of photos of this and came to several conclusions.

Indigenous cultures were high in many nutrients especially fat soluble vitamins (A,D, E, and K). They consumed organ meats. They ate whole foods, nothing processed, at least not how we process them in the Western diet. The processing that was done were things like soaking, sprouting, and fermenting. He noted they ate a variety of fermented foods, sourdough bread being one of them. Of course, this varied from culture to culture. Some ate more plants, while others ate predominantly animals only such as the Inuit. There was no culture that was purely vegan and that is true to this day. There are no indigenous cultures that are vegan. Animals are an important part of their diet. I don’t mean to generalize, but there are comparisons that can be drawn between all of the groups. Dr. Price concluded that their dietary lifestyle was the main reason they were not developing chronic health issues. This is but a summary of Dr. Price’s work. The books is very detailed and has a lot to offer to those who want to learn more. It was and remains my entry point into nutrition and it is foundational as well.

As I read this book, I was thrust into a world that was deep and enriching. Something about it hit home with me and since then when I wonder about health care issues a question I commonly ask myself is, “what did our ancestors do?” I think it is a very important question to ask. The indigenous cultures Dr. Price studied used to be what was common. We all used to live like that at one time or another. Especially for the millennia we lived as hunter-gatherers. Some technology such as sprouting and fermenting came much later in human history, but many dietary practices are quite ancient. It is arrogant to assume we know better than they do when they are far healthier than we are.

A Shift towards Paleo and a Dabble of Carnivore

As I studied nutrition I was introduced to the paleolithic diet, or paleo for short. In many ways, this resonated with me. In some ways, it didn’t. Some of those ways were religious concerns I had, which is outside of the intent of this article. I don’t mind talking about it, but I don’t think this is the place for that conversation. But it was something I needed to wrestle with and overall it helped me understand things a lot more. Back to my point, paleo resonated because it purported to be what our ancient ancestors ate like. There is a lot of truth in that, but like so many things, what people claimed to be paleo varied quite a bit. In general, the paleo diet was a focus on animal foods, fruits, nuts, and vegetables. Foods you could easily hunt or gather. There are paleo principles I still use to this day. I often recommend it to patients while they are healing because of its anti-inflammatory nature. But my understanding wouldn’t stop there.

A recent article really opened my eyes. It was shared to me by a friend. Until reading this, I balked at the idea of a carnivore diet. It is still extreme in my view though it has its place in the healing process for some people. I often wonder if it is just masking other things going on such as chronic subclinical infections, not quite sure. Either way, the article was titled, The evolution of the human trophic level during the Pleistocene by Miki Ben-Dor, Raphael Sirtoli, and Ran Barkai.

It is a fascinating multidisciplinary study of human evolution during the Pleistocene. They concluded that for over 2 million years humans got 70% or more of their calories from animal sources. Researchers classify this as hypercarnivore. Carnivore does not mean you eat 100% animal foods, rather it is the degree to which animal foods are dominant. It is a fascinating article, I encourage you to read it. I am excited to see what new evidence is found about this era of human evolution. That being said, it sort of shook my worldview a bit.

It caused me to do open up and do a deep dive into the carnivore diet that has grown in popularity. I learned a lot. I even experimented with it twice as well as going animal-based for a 6 months, which is similar but also includes fruits and honey. I wouldn’t say it is for everyone, but there were some key take-aways. One of which was humans evolved to eat a lot of meat, the pH of our stomach acid is evidence for that. On average it is about 1 to 1.5 pH which is very acidic. It is more acidic than a lion’s stomach acid and almost as acidic as many scavengers. We are more on par with scavengers than lions to say it another way. Another is the importance of protein. Something I already knew, but it became solidified in me.

Why is this important?

If you can bare with me a little more lets go back into our anthropologic history. Our genes are virtually unchanged from our hunter-gatherer ancestors. Please do not misunderstand me, there have been some genetic changes as humans switched to agriculture. Being able to acquire more nutrients from grains is one and for many the lactase enzyme persists into adulthood allowing them to consume dairy easily. However, it is important to look to the past to learn a bit about how our diet developed. It is also important to understand the technological advancements our ancestors developed. These technologies allowed us to eat foods that otherwise were out of our reach or would be detrimental to our health.

photo of group of men wearing assorted scarves holding sticks

Earlier we talked about certain indigenous cultures around the world that eat a more traditional diet. Among these included groups who live a variation of a hunter-gatherer lifestyle, HG for short. Humans lived as HGs for over 2 million years. The dating is difficult, but it seems as we learn more that number gets larger. But let me illustrate the point I am trying to make. If we were to look at the vast human history as a football field, a fraction of the last yard line before the end zone would represent the timespan from the agricultural revolution 10 to 15,000 years ago until now. For the majority of human history we were hunter-gatherers. Millions of years ago our ancestors lived in trees. As far as we can tell we split from our common ancestor with the chimpanzees about 7 million years ago. We were tree dwellers who survived primarily on plants and insects as best we can tell. 

Concerning the development of our eating habits Dr. Bill Schindler states, “In fact, other than when we are infants and well equipped to drink mother’s milk, the only foods our digestive tracts are biologically designed to consume are the insects and limited amounts of wild fruits and vegetables that made up the diets of our early ancestors. How we overcame these physical and biological deficiencies and learned how to eat is the story of how our ancestors became human both culturally and biologically.”

The first major change was at some point our ancestors descended from the trees and started scavenging. We have evidence of meat eating dating back 3.5 million years. This wouldn’t change majorly until we developed tools for hunting and fishing. Then around 2 million years ago (this number seems to keep getting older) we see a massive explosion in our brain sizes. We still do not know what the catalyst was that drove this but we do know several factors that were crucial to our brain’s increase in size. These factors include eating meat specifically organs, fat, hunting, and fire. 

Hopefully you noticed that all those factors have one thing in common, animals. Depending on who you read, they will place the emphasis on one factor over another, fat being a popular one. As well evolved our bodies changed. We lost our hair so we can cool off easier on the plains especially while running. Our gastrointestinal tract changed. We no longer needed the long colons that help with digestion of plant matter that our primate cousin’s have such as chimps and gorillas. Instead we have a short colon, not much fermentation goes on there comparatively. Our tool development became more sophisticated and we became great hunters. Too great by many estimates as we might have been a major factor in the extinction of the megafauna. However, there were other factors too. 

The Revolutions

The extinction of the megafauna and other changes in human culture moved us towards agriculture. The agricultural revolution took place about 15,000 years ago.  As things changed we adapted. We developed more technologies to help us digest the plants we began to grow. Dr. Schindler states, “We developed technologies to do outside of our bodies what other animals do naturally inside theirs.” Humans are amazing at adapting, but that doesn’t mean it is optimal. Do not forget that we spent the vast majority of our history subsisting on animals primarily. 

The change to agriculture had a direct effect on our health. We shrunk in stature and brain size. Chronic disease starts to rise for the first time, not that it didn’t exist before but it was very minimal. We start seeing evidence of dental caries and bone changes due to vitamin and mineral deficiencies. We also see an increased propensity to infection. As large civilizations began to develop we enter recorded history. We are able to see more of what they are eating in the historical records not just from studying their bones. We also are able to study what demographics are affected the most. Of course, some of our modern ailments are known as plagues of prosperity because only those with wealth could develop them. But the poor were not better off, they usually subsisted on grain and were undernourished as well generally speaking. 

This would carry on for thousands of years. Different civilizations had varying depths of this. This is not to say that it was all negative. Some cultures thrived. Remember Weston Price? He studied several cultures that were thriving and chronic disease was seemingly absent. This was due to the technology that we developed and these cultures were likely able to appropriate a variety of foods. Other cultures it was not so easy at certain times due to a variety of reasons such as politics, famines, socioeconomic status, etc. 

Human technology would continue to develop until we got to another revolution, the industrial revolution in the 1700s. Here technology rapidly developed as we all know. However, this has been far more detrimental to our health. We noted the increase of chronic disease with the agricultural revolution, with the industrial it exponentially increased. As we developed processed foods, seed oils, chemicals, GMOs, and many other things our health rapidly decreased. Now we are sickest we have ever been. And this is due in large part by eating the complete opposite diet of what we evolved to eat. Instead of a preponderance of animal foods, we eat a tremendous amount of refined carbs and industrially produced seed oils. Instead of fruit and vegetables we gathered and even cultivated, we eat a bag of potato chips and take a multi to make up the difference. So what do we do? What does eating like a human look like?

The Ancestral Diet

Meat

As you can see animal foods have been a primary part of our diet for millennia. They are essential. So, allow animal foods to become the star again. Expand and learn to enjoy or consume organ meats. They are the most nutrient dense food you can eat. These foods are packed with nutrition that is bioavailable. Unlike plants there is generally nothing keeping you from absorbing and using animal nutrients. Plants contain many toxins which we will talk about as well as the technologies we developed to decrease the toxins and harness the nutrients. 

It is important to choose your meat wisely. You should definitely look for good reputable local farmers. That doesn’t mean you can’t find any in the store, but it does allow you to get to know your local farmer. I find this to be an invaluable relationship. Definitely look for organic and pasture-raised. But that is not the end-all be-all in shopping. I do err on that side with chicken and pork, but with ruminant animals such as cattle it is not as big of an issue, but still grass-finished is preferred. 

You may be wondering how much meat? If you look at your plate and divide it into thirds, 1/3 of the plate should be animal food. That is a general goal. Another way to tell is looking at the amount of protein you need on a daily basis. Generally we should be getting over 100 grams per day. 100 grams is roughly about 1 lb. of meat. We need to get about this amount to make sure we hit what is known as the leucine threshold. When this threshold is hit protein synthesis is kicked on. This is one of the primary goals. We need protein synthesis to maintain, repair, and make new protein. Of course there are other factors such as movement and weight training.

Another important goal is the total amount you need. Roughly speaking we need about 0.8 to 1.5 grams of protein per lb. ideal body weight. The broad range depends on need. If someone is lifting a lot of weights and trying to build and maintain muscle they will need more protein. You may need to play around with the ratio some to find what best suits your needs. If you find yourself not recovering from workouts or more hungry throughout the day, you may need more protein.

Here is an example, my ideal weight is around 175-180 lbs. To make it simple I am going for 1 gram per lb. Therefore, I need around 175-180 grams of protein. There are great apps out there that can help you track protein. Cronometer and My Fitness Pal are great ones.

Lastly, you will find as you prioritize protein that you will be full longer and will need to eat less. Protein is the great “satieter,” to make up a new word. It has been hypothesized that hunger is primarily driven by our need for protein. Which makes sense as if our body’s know intuitively what will provide the most nourishment. So the moral of the story is, don’t be afraid of that rib-eye steak.

Fat

This deserved a section all to itself. Don’t be afraid of fat. For far too long it has been ridiculed and wrongly accused of many health ailments especially saturated fat. However, these studies are based on biases and poorly acquired data. As the famous quote attributed to Mark Twain says, “There three kinds of lies: lies, damned lies, and statistics.” We can make the data look like what we want it to. But the fact of the matter is, fat is one of the biggest factors that made us human. So says Dr. Jess Thompson in her video titled Fat of the Land. It is a great presentation, I highly recommend it. 

It is a misnomer to say that fat is what makes us fat too. Certainly there are unhealthy fats out there and we eat too many of them. But all of these are typically ultra-processed seed oils like vegetable and canola oil. However, the fat we have been eating for generations is great for us. This is fat from animal foods like tallow, butter, and lard. Fatty cuts of beef and fatty fish like salmon or cod are fantastic sources. There are good sources from plants too such as coconut and avocadoes.

Fat is not only a great source of calories that is satiating it also has many other nutrients that we are in desperate need of these days. These are the fat soluble vitamins A, D, E, and K. And there is no replacement in the plant world generally for these vitamins. You can find some but the most bioavailable sources are found in animals especially for A, D, and K. Of course, we synthesize D from cholesterol using sunlight. But A and K needs to come from animal products. Don’t listen to anyone who is telling you that beta-carotene is vitamin A. It is not, it must be converted to it and it is a poor conversion process. 

Let fat be your friend again, your body and taste buds will be happier for it.

Dairy

Let butter be king. Dairy is a great food to include, unless you are sensitive to dairy, of course. Quality is important with dairy. I highly recommend a good source that is organic and grass-fed. We go to a local farmer for raw milk ourselves. Then we grass-fed butter, cheese, and other dairy products. Plus, once you have grass-fed butter you really don’t want to have anything else, it is so delicious!

For those who have lactose intolerance it may be more difficult. Some report that having raw milk was no issue for them because the lactase enzyme survives. Others may not be able to enjoy milk but they can enjoy the fermented products such as cheeses and yogurt. That is something you will have to determine. Nonetheless, dairy is a great food to include and has been used for thousands of years.

Plants

“Plants should scare the hell out of you.” Dr. Schindler

Don’t let this scare you too much. It is just an important reminder that plants have a natural defense mechanism especially the leaves, seeds, stems, and roots. Plants need these to stay alive and reproduce. Animals, of course, can run away, plants cannot. As plants evolved, they developed certain mechanisms to defend themselves. Some of these mechanisms are chemical compounds to ward off pests. These are natural pesticides and insecticides.

Fruit are by far the least toxic though some fruit can carry certain toxins such as tomatoes and peppers. These are part of the nightshade family and many people are sensitive to their toxins. The symptoms are broad, but pain is a major one. Other plants such as spinach and turmeric are high in oxalic acid which is the main cause of kidney stones. This is why it is good to rotate your veggies. Green smoothies, which is all too common, has caused many to become ill due to oxalic acid toxicity. Does this mean this will happen every time you add spinach to your smoothie? No, not at all. Please don’t let this scare you away from having salads. Kale is great. Spinach is great. Rotating is probably best as well as variety.

This was not much of an issue anciently because some plants are seasonal. It is harder to get an over abundance especially when the best bang for your buck is taking down a buck for its nutrient density. Further, we also developed technologies to remove the toxins.

So what did our ancestors do? 

It depends on the plant. Some like fruit need very little attention, usually as simple as cutting out the seeds. Of course, many fruit have been cultivated to be sweeter today, so going to town on a bunch of fruit everyday is not a great idea. Usually one or two is just fine. Other plants like cassava or yucca, which is a root vegetable, must be cooked to consume. It is high in cyanide and cooking breaks down the toxin. Many people around the world consume this root vegetable, this is not meant to scare you but to bring awareness. We enjoy this vegetable quite a bit since we are gluten-free.

Still others such as nightshades, humans learned to use ash and clay to help remove its toxic effects. There are still people in Peru who do this. Otherwise, it is important to rotate greens and eat more seasonally.

I hope this gives an overall picture of plants and why we need to be somewhat careful. That being said please do not think I am saying you shouldn’t eat any. We should! They are a great part of what humans eat. They should be organic and locally grown in possible. Our ancestors enjoyed a great variety of them depending on the location.

Grains and Seeds

I love sourdough bread. I love baked goods. Sadly, it is what I am sensitive to. But why? What is so wrong with it? Wheat like rice, barley, and corn is a seed. Seeds germinate into new plants. Plants do not want you to consume these. Other seeds are legumes, nuts, and of course, seeds like pumpkin and sunflower. Seeds have toxins to discourage consumption and to protect them from being digesting so they can be passed with the stool. One of these is phytic acid which prevents absorption of many nutrients. Seeds also contain lectins which can cause many issues including inflammation and gut disorders. 

For many seeds our ancestors figured out how to process them. It might have been observing how nature works. Such as how ducks are able to consume whole grain wheat. They seemingly sprout and ferment the wheat inside themselves. Either way, our ancestors figured out that they could make nutrient-rich bread and minimize the toxins by sprouting and fermenting the wheat. This is how classic sourdough bread is made and it is how it was made long ago before the invention of refined flour and dry yeast. Further, we also hybridized wheat to increase the yield and gluten content. We also spray it heavily with chemicals such as glyphosate which only make matters worse. So not only is it important to sprout and ferment, but it should also be an organic, heirloom variety.

Next is corn or maize. Corn unfortunately has been modified genetically so it can handle being sprayed with glyphosate. So 90% of the corn consumed is this variety. Glyphosate is not kind to your gut bacteria neither is it you. It is definitely better to get a non-GMO, organic variety of maize. 

Maize is difficult to digest. So how did traditional cultures process maize? Through a process called nixtamalization. Without this process the nutrients remain locked inside and it remains difficult to digest. Maize is simmered and soaked in a solution of water and lime or calcium hydroxide. This process detoxifies the maize kernels and makes the nutrients available for digesting. It is important to buy corn that has been through this process.

Other seeds need to be processed in different ways. Legumes have a high lectin content and soaking and pressure cooking can reduce that content. Nuts on the other hand are difficult. There is not much to be done with them, so it is best to eat them in moderation.

When You Can Cut Loose

I have a hard time with very strict diets. I think there needs to be some flexibility. Now there is a caveat. If you are in your healing phase or you just got sick, it is important to be careful and stick to a nutrient dense, anti-inflammatory diet. However, if you are feeling well it is typically okay to enjoy special events. This is often called the 80/20 or 90/10 diet. Where you eat appropriately 80 to 90% of the time and the remainder you can cut loose a bit. And I really do mean at special events. This should not be a constant thing. Even healthier sweeteners like coconut sugar and maple syrup can have their drawbacks. So it is not a daily thing. But it is important to enjoy time with your community and especially your family. This is an important part of overall health.

We underestimate the importance of community. People who have a strong community including a spiritual one, close family relationships especially in a multi-generational home, and a purpose are much healthier. They have found that this can fight chronic disease in of itself. We typically only focus on diet, but this may be equally important.

So don’t feel overly stressed at important events like Christmas or a work outing. Just enjoy it.

Conclusion

I know there is more that could be said. Other foods to talk about. Other technologies we use to process them. However, my goal was to give a general overview. I hope it has been beneficial. If you would like to learn more check out the book in the sources below. This is one of my favorite books I have read recently. Dr. Schindler is a great researcher. Otherwise, eat like a human. Enjoy animal foods, traditionally prepare others, hunt, gather, live. Enjoy time with your family and others. Grow an organic garden, farm. There are so many ways to approach this. But the big takeaway is humans evolved to eat a variety of foods especially animals foods. And we developed many technologies to consume others. Hopefully you now have a framework to go by. Prioritize protein from animals, enjoy fat, enjoy plants but be cautious with some, and use the appropriate tools to process them.

Sources:

  1. Schindler, Bill. Eat Like a Human: Nourishing Foods and Ancient Ways of Cooking to Revolutionize Your Health. New York, NY: Little, Brown Spark, 2021.
  2. Price, Weston A. Nutrition and Physical Degeneration. Lemon Grove, CA: Price-Pottenger Nutrition Foundation, 2009

  3. Ben‐Dor, Miki, Raphael Sirtoli, and Ran Barkai. “The Evolution of the Human Trophic Level during the Pleistocene.” American Journal of Physical Anthropology 175, no. S72 (2021): 27–56. https://doi.org/10.1002/ajpa.24247.

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