The Evolutionary Mismatch Behind It All
Over my quest for understanding about what creates health I have found it useful to not only understand what drives the development of a particular illness or disease, but also to have a big picture understanding of why the imbalance is even happening in the first place. This last post of this series will discuss the why of the imbalances we have discussed when it comes to heart attacks.
Up to this point we have laid the foundation of what causes a heart attack, shown how burning fat and ketones are best for your heart, discussed how an Autonomic Nervous System imbalance can lead to a heart attack, and discussed the key role of oxidative stress in the whole equation. Now let’s take a step back and look at the big picture. Here is where we are in the series:
Part 1 – The Foundational Imbalances That Cause Heart Attacks
Part 2 – Cholesterol, Fat Burning, Ketones, and Metabolic Flexibility
Part 3 – The Autonomic Nervous System Imbalance
Part 4 – Toxins, Oxidative Stress, and Nitric Oxide
Part 5 – (This post) The Evolutionary Mismatch Behind It All
About 6 million years ago humans and the apes of modern day (chimpanzees, bonobos) shared a common ancestor. Something happened that set our evolutionary paths on different courses. Whatever it was that created the divide is not important, but what happened after the divide is what resulted in the differences we see in modern humans and modern chimps and bonobos today.
After that split 6 million years ago, it wasn’t until about 2 million years ago that humans started to do something that would put us on an entirely different path than our closest living ancestors. We started eating large amounts of animal fat and meat. Around this time species like Australopithecus afarensis and Australopithecus africanus were walking around. These species were closer in characteristics to that of modern-day chimps and bonobos in that they had larger digestive tracts, less acidic stomach acid, and smaller brains.
When some of these species started eating more animal fat and meat by scavenging the carcasses of animals and breaking open the skulls and bones to get at the fat left behind by other animals, then the push that would eventually lead to us modern humans had begun. You can see in the diagram above that 2 million years ago is when the lineage that eventually became modern humans broke off. The high stomach acidity we have as humans today (1,2) evolved during this time as it would have been very useful to be able to kill bacteria growing on the carcasses that they were scavenging on.
Eventually pre humans evolved the skills to hunt their own animals and there is evidence that the species that preceded modern humans were hunting and eating a lot of large fatty animals starting about 2 million years ago. (3,4) This lead to a flip-flop in our digestion. Instead of needing a short small intestine and large colon (like we see in apes) to ferment and extract nutrients, by eating very bioavailable nutrition in the form of animal fat and meat humans developed a longer small intestine for higher absorption and a smaller colon because we didn’t need to ferment much. (5,6)
It also lead to increased stature (7), as well as an increase in the size of their brain (8,9,10) because of all the fat they were eating and because of the communication and strategy they developed to become master hunters. Humans did not evolve to eat animals, they evolved to what we are today because they ate high amount of animal meat and fat.
Then something changed. Over the 2-million-year period there was a massive die off of the large megafauna that pre humans and humans were hunting that was supplying them with these coveted nutrients of meat and fat. (11) Some say it was a massive global change of some sort on the planet that caused this, and some say that our ancestors hunted the animals to extinction. Whatever the cause our ancestors had now lost the food source that was driving their evolutionary success.
Because of this, around this time, we started to see the first evidence of farming and civilizations. This would prove to be the single most abrupt change in the way of life for humans, and I believe that we can trace the causes of the imbalances that cause heart attacks discussed in this blog series back to this time in human history.
Modern humans appear in the archeological record around 2-3 hundred thousand years ago and agriculture did not appear until around 10-15 thousand years ago. This means that for the majority of the time modern humans have been around we were not farming. Instead, we were killing and eating large animals. That changed in a very short span of time.
This means that humans are not well adapted to the type of life that farming and civilization created for us, and the necessary generations needed for them to adapt to this change were not provided and still haven’t been. There is evidence that human health suffered during our switch from hunting to farming. (12) Let’s revisit each of the imbalances that drive heart attacks and discuss them in the context of the change that farming and civilization has brought to our way of life.
The first one is fat burning, and it is pretty obvious how this changed. When humans went from hunting large animals and being reliant on fat and meat to now being reliant on carbohydrate rich crops like corn and grain it had a poor effect on our health. It’s no wonder that the research we saw in Part 2 in this series showed that high carbohydrate diets increase risk factors for heart disease. Humans are not evolved to eat these foods in high quantities. Even the Ancient Egyptians, a farming culture that ate little meat, had heart disease. (13)
There is evidence that our brains have gotten smaller since we converted over to farming (14), which makes sense because we were not eating as much fat and because farming did not require as much complex thought as hunting did. Also, when humans started relying on high carbohydrate crops their bodies were forced to burn glucose as fuel. This is the first mismatch that the agricultural revolution created that ultimately leads to heart attacks, a reliance on carbohydrate for fuel rather than fat.
Secondly, the birth of agriculture and civilization completely changed our living environment. Instead of residing in small bands of people, humans were now thrust into large communities with many unnatural stressors. The stress response of wild mammals described in Part 3 is the way a stress response in humans should work. Our stress response evolved to only happen when needed in order to get us away from a life-threatening situation. In contrast, civilization has created an environment that is too stressfully stimulating to our complex brains and keeps our stress response chronically activated.
Civilization has had many benefits to humanity, but it has also created money, competition, and unrealistic expectations. The research cited in Part 3 showed us the consequences of these things to our health. The endless quest for the money necessary for us to survive, the competition for that money and other resources, and the unrealistic demands placed on us in modern day society have led to a severely unbalanced ANS in humans. And that is only the external stimuli.
Internally, agriculture brought problematic plant foods into our diets that damaged the gut and our nervous systems with antinutrients, which we also discussed in Part 3. These were substances that would not have been in contact with our bodies during the millions of years of our evolution and suddenly they showed up with no time for us to evolve to them. The massive change in food and way of life for humans has led to a mismatch in the ANS that drives hearts attacks.
The last imbalance is oxidative stress. We have seen research in Part 4 that shows us that high carbohydrate diets can lead to higher levels of oxidative stress so there is yet another downside to eating high carbohydrate crops. Civilization has also lead us down a path of more and more advanced technology. Again, this has done amazing things for the advancement of humans, but it has also increased our toxin exposure tremendously.
For the millions of years of our evolution the heavy metals that are toxic to us were buried in the Earth and we had no contact with them. During the Industrial Revolution these metals were dug up and suddenly our bodies had to deal with them. Similarly, we humans have combined molecules in ways that nature never did. According to Herbert Needleman, who has spent his life studying the effect of chemicals on children, at least 70,000 new chemical compounds have been invented and dispersed into our environment since 1950, and only a fraction of these have been tested for human toxicity. The research in Part 4 showed us the damage these toxins can cause.
When it comes to oxidative stress the quick change to our reliance on carbohydrates and sudden exposure to many toxic substances is creating an amount of free radicals in our bodies that they never had to deal with when we were living out in nature eating our diet of fat and protein from animals. This increase in oxidative stress is the mismatch that drives atherosclerosis and plays a key role in the events that lead up to a heart attack.
Evolution is a very slow process. It took millions of years for pre-humans and then humans to develop the anatomy and physiology that we have today. For most of the time since we split from our closet ancestors 6 million years ago we were eating fat from large animals and living in nature. (15) The shift from that to civilization has led to the myriad of chronic illness that we see today. None more evident than heart disease and heart attacks.
In my book, The Health Evolution: Why Understanding Evolution is the Key to Vibrant Health, I go into much more detail on this evolutionary mismatch idea and show how the quick change that civilization brought has lead to many of our modern-day issues. In the book I say, “When thinking about the problems we face as a species, we tend to think of things such as our epidemic of chronic disease, the extinction of more and more species, the pollution of our environment, and the economic inequality among populations as problems. They are not the problem; they are the symptoms. The symptoms of us living separately from the natural world that we evolved in for millions of years.”
The biggest realization that I had which got me thinking about heart disease the way I do, is that in the context of human evolution the idea that heart disease is caused by saturated fat and cholesterol in the diet makes absolutely no sense. How could those foods in the diet lead to heart disease when for almost all of human evolution we were eating exactly those foods? If the foods we were eating throughout our evolution caused heart disease, we would have died off as a species long ago. The fact that we are here today means that it is highly unlikely that our hunter-gatherer ancestors had heart disease like we do today.
This realization drove me to finding the true cause of heart attacks. In order to prevent this disease, it is essential that we think about our evolved physiology and do all that we can to recreate the environment best suited to that evolved physiology within the confines of our modern-day world. To me that is an animal-based ketogenic diet, a lifestyle that balances our ANS, and the avoidance of as many toxins as possible. This is the path to heart health.
Hope you enjoyed this blog series! Stay healthy out there!