I know what you’re thinking, how can a diet of only eating animals be good for us, and can it really be preventative when it comes to heart attacks? I believe that an animal-based diet is an evolutionarily consistent diet for humans and therefore prevents heart attacks by default. I am going to explain the whole thing. This is a large and multifaceted topic that strings many concepts together. So, I am going to break it up into a series of 5 posts so you can take it in a little at a time. Then I will tie it all together in the end. Here is the tentative outline:
Part 1 – (This Post) The Foundational Imbalances That Cause Heart Attacks
Part 2 – Cholesterol, Fat Burning, Ketosis, and Metabolic Flexibility
Part 3 – The Autonomic Nervous System Imbalance
Part 4 – Toxins, Oxidative Stress, and Nitric Oxide
Part 5 – The Evolutionary Mismatch Behind It All
Let’s get started.
Before we get into the animal-based diet side of things, this first post is going to lay a little bit of a foundation for the major concepts at play when it comes to heart attacks. These are essential to understand before we can see how an animal-based diet prevents heart attacks.
These concepts are ones I have discussed in other blogs, social media posts, my ebook, and my heart course. Since I have discussed these in detail in these places I am going to only briefly discuss them here so you can get a basic understanding. I will refer you to resources mentioned above for a more detailed understanding.
The first thing we need to have is a fundamental acceptance that heart disease and heart attacks are not caused by saturated fat or cholesterol in the diet. This idea all started when Ancel Keys, a physiologist, did a study in the 1950’s analyzing the association between the amount of fat in the diet and heart disease in different countries. He found that there was a correlation between the two.(1) However, when we look back it is clear that he picked the data from countries he thought would show him the correlation. He kind of “cherry-picked” the data. When two scientists repeated his study a few years later, but included the data from all the countries that was available, they found absolutely no correlation.(2) Many more recent studies have shown that there is no correlation to dietary saturated fat or cholesterol in the diet and incidence of heart disease.(3,4,5,6)
We will talk more about this is part 2 of this series, but for more about the topic of cholesterol and saturated fat in the diet, and how it is not the cause of heart disease, I will again reference you to my ebook, The Heart: Our Most Medically Misunderstood Organ. You can also subscribe to view my heart course or head to my YouTube channel. There are also many, many others talking about this and putting great information out there debunking this long-held misconception. The Weston A. Price Foundation, Dave Feldman, and Ivor Cummins are all great resources for the truth about saturated fat and cholesterol. For now, the take home is that the lipid hypothesis of heart disease is not supported by good science and if we are ever going to stop this disease we need to start thinking about it in a radically different way. We must stop barking up the cholesterol tree. Animal food is good for your heart.
With the lipid hypothesis debunked and out of the way, this begs the question of what does cause a heart attack? If it’s not saturated fat and cholesterol like we have been told, then what is it? Knowing the true cause of heart attacks will help us understanding why an animal-based diet is best for preventing them.
There are three imbalances in the body that, when they happen in the right capacity, start the series of events that lead up to a heart attack. These imbalances are gone over in detail in my heart course, specifically in Chapter 8. I will briefly go through them in this post so that you have this as a foundation for the discussion in subsequent posts. We will get into these imbalances, specifically in the context of an animal-based diet, in the upcoming posts in this series.
The first imbalance that occurs (and these imbalances don’t necessarily happen in any distinct order) is when our bodies, especially our organs, burn glucose for fuel rather than fat. Our bodies prefer to burn fat for energy and are more efficient when they do.(7,8) This is especially true with our heart. So much so that when we eat fat a large portion of it is absorbed by chylomicrons (fat transport molecules) which get absorbed from the intestines into the lymphatic system. The lymphatic system eventually leads to one place, the thoracic duct. This duct drains right into the veins that lead directly to the heart so that the heart gets first dibs on burning this fat as energy. That’s how important it is for our heart to have fat available to burn. However, in our modern world, there are a few things that are disrupting our bodies’ fat burning preference.
One is that the Standard American Diet is too high in carbohydrate, especially processed carbohydrate. Carbohydrates are burned as glucose in our bodies and when we supply our bodies’ with too much of this, and not enough of the right types of fat, then it is forced to burn glucose as fuel. The process of taking fat through the lymphatic system to give the heart first dibs on the fat ensures that even when we burn too much carbohydrates for fuel the heart will be the last part of the body forced to do that. This allows the heart to only rely on that fuel if absolutely necessary.
The other thing that can drive our body to burn glucose as fuel over its’ preferred fuel source of fat is when we are very stressed and develop an imbalanced stress response (9) (more on this in a moment). If your body thinks it is in a stressful environment it thinks it needs to fight or flee the situation and will need quick burning energy to do so. Therefore, it will burn glucose because it is quicker for us to burn and it would ideally give you a better chance of getting away from a threat.
Again, the ability of the heart to burn fat as fuel is so important that your body ships fat directly to it so that it gets first dibs on using it for fuel. If the heart is faced with a situation where it is forced to burn glucose for fuel, either chronically or a sudden surge of glucose burning due to a stress response, this can be a dangerous situation for us, as we will see.
Now, let’s dig in to the imbalanced stress response I previously mentioned, this is the second part of the foundation we need to lay. We humans, like all mammals, have an Autonomic Nervous System. This is the part of the nervous system that allows us to interpret our environment and determine if we should be having a stress response “fight or flight” or a relaxation response “rest and digest”. Again, our modern world can create an imbalance in this system because we are constantly bombarded with unnatural stressors, ones we would not have encountered in the wild. Also, we are the only species on Earth that can overthink these stressors and think our way into a stress response.
This can cause us to get stuck in the “fight or flight” aspect of our physiology and somewhat lose the ability to get in a “rest and digest” state. When we lose this balance it can cause all kinds of symptoms and ailments. (10,11,12) This imbalance heavily contributes to the events that lead up to a heart attack. Just like our modern dietary environment of processed carbohydrates does not suit our evolved physiology of preferred fat burning, our evolved Autonomic Nervous System operating among the modern world stressors that we encounter today are not a good recipe for health.
The third and final foundation we need to talk about is something called oxidative stress. In our bodies we develop what are called free radicals. These are made as a result of our body performing normal and necessary tasks that it needs to do to get stuff done. I compared it to when a car burns fuel it makes a toxic waste product, exhaust. Left unchecked these free radicals will damage tissues in our bodies.
Our bodies have built in mechanisms to take care of these free radicals so that they don’t cause excessive damage to our body. However, there are things about our modern world that throw this off balance as well. Going back to the diet again, when we eat processed carbs this tends to increase the number of free radicals produced by burning those for energy.(13) Also, toxins we are exposed to from our external environment can act as free radicals as well.(14,15,16
We are exposed to many toxins that our bodies did not have to deal with through the millions of years of our evolution that made us the humans we are today. We have mined heavy metals out of the Earth, we have countless man-made synthetic molecules in our environments, and believe it or not there are many molecules in plants that act as free radicals in our bodies too
Having excess amounts of free radicals, whether they are made by us or external toxins, in our bodies can cause us to be in a state of oxidative stress. This means there are more free radicals in our body than it can take care of and the body cannot maintain a balance. This can cause damage to our tissues. This damage can cause all sorts of symptoms and oxidative stress has been links to many chronic diseases.(17,18,19,20,21)
The most relevant negative effect it has concerning this discussion is that it can deplete what’s called Nitric Oxide (NO).(22) Nitric oxide is produced in the cells that line our arteries and is responsible for dilating our blood vessels so blood can flow easier. More important to our discussion is that NO is also what allows the signal from the relax, or “rest and digest”, part of our Autonomic Nervous System to get relayed to the cells in our heart.(23) When we get high levels of oxidative stress this can deplete NO and interfere with proper signaling of our nervous system to heart cells.
So, we have explained how not being well-adapted to burning fat from eating a carbohydrate rich diet, having an imbalance in our Autonomic Nervous System stress response from unnatural stressors of our modern world, and a poor diet and excess toxin exposure leading to oxidative stress can cause health issues. But how do these things predispose us to and ultimately cause a heart attack?
To explain this I will have to get a bit technical, so bear with me. The control of the balance of the Autonomic Nervous System in cardiac cells, and many other cells, relies on two messenger molecules called cAMP and cGMP. cAMP levels rise in the heart cells when we have a stressful response to something, and cGMP levels rise when we are in a relaxation state. The only difference is that when it comes to cGMP, the relax molecule, something else is also needed to increase its levels. That something else is nitric oxide, like we mentioned above. These two molecules—cAMP and cGMP—keep each other in check within heart cells. When we experience a stressful response and the nervous system causes spikes in cAMP within the heart then cGMP, provided there is enough NO, also has an increase just to keep the system in balance.(24) This is depicted in the image below.
Sroka, K. (2013). What is the connection between oxidative stress and heart attacks? Retrieved
But, like we have discussed, the system can become unbalanced. When we have prolonged periods in our life with many surges of stress responses that increase levels of cAMP and then also get less than optimal stimulation of the relax response then we can lose the ability to effectively move between these two states. We can get stuck in our stress state.
This is called decreased vagal tone because the vagus nerve is the nerve that carries the non-stress signals. When this happens, the failsafe within the cardiac cells is that those consistently high levels of cAMP are balanced by also rising levels of cGMP. But remember that cGMP can only do this if NO is present. If NO gets depleted, it is really bad news. We have talked about how NO can becomes depleted from excess free radicals causing oxidative stress.
So, an imbalanced stress response combined with oxidative stress that depletes NO sets the stage, now it is time for the big event. When humans experience decreased vagal tone for long periods of time while also experiencing decreases in NO levels and then we go through a stressful event (research shows that heart attacks happen more often during stressful times) (25), then we get a surge in the stress response and subsequent elevation in cAMP in our heart cells without the balanced rise in cGMP. This is shown in the image below.
Sroka, K. (2013). What is the connection between oxidative stress and heart attacks? Retrieved
When this happens the cascade of events that is a heart attack plays out. The sudden unchecked rise in adrenaline, and therefore cAMP, from the stress response has been shown to cause an increase in lactic acid production within cardiac cells.(26,27) Remember, the heart usually prefers to burn fatty acids but in this situation the body thinks it needs to burn energy quicker. Since it is quicker to burn glucose the heart cells revert to burning it rather than burning the more efficient and preferred energy source of fat.(28) This happens more readily if we have been eating a diet of carbohydrates instead of good fats and your body is not well-adapted to burning fat. When this burning of glucose happens, it causes the build-up of lactic acid within the heart cells.
This is similar to when you do a sprint or a hard and fast workout, lactic acid builds up in the muscles causing the muscle to have that burning feeling. When this happens in a muscle in the legs or arms we can just stop moving it and the lactic acid will move along stopping the build-up. Since the heart can’t just stop contracting, the lactic acid quickly builds up causing a major problem. The presence of acid in the heart tissue prevents calcium from entering the cells. Since calcium is the mineral that allows muscle to contract, now the heart muscle cannot contract properly. It has been shown that low calcium in heart cells results in slower conduction velocity and elevated arrhythmia risk.(29) This eventually leads to localized swelling (from the lactic acid build up), dysfunctional cells walls (because of the lack of calcium), and eventually heart tissue death. In other words, a heart attack.
To review. In heart cells, when cGMP cannot stay balanced with cAMP due to decreased vagal tone from chronic stress and depletion of available nitric oxide from toxin exposure, then any surge in stress response can cause the heart cells to move away from their preferred fuel source of fatty acids and force them to burn sugar instead. This results in increased lactic acid build-up in cells that causes the burning chest pain people feel in heart attacks. The lactic acid build-up also blocks calcium from getting into heart muscle cells causing it to cease contracting. This causes swelling, dysfunction, and eventually heart tissue death.
So, that is what causes the vast majority of heart attacks. You can see that it has nothing to do with saturated fat and cholesterol getting clogged in arteries. Now that you have that foundation we can start getting into how an animal-based diet can help prevent the imbalances that lead to this series of events. In the next post we will talk all about fat burning.
See you next time! Stay healthy out there!