Updated: Mar 15
Humans have been eating meat for 2.5 million years. It is the eating of predominantly meat that drove our evolution from the pre-Homo species of Australopithecus to the first species of Homo. At first, our pre-human ancestors were scavenging what was left of carcasses. They had two evolved characteristics that helped them be successful at this. They were smart enough to develop tools to crack open bones and skulls to get access to bone marrow and brains that other animals could not get to. (1) Humans also evolved a very high stomach acidity, even more acidic than known carnivores today. (2) This helped them kill pathogens living on the meat they were scavenging.
When pre-humans began eating animals it was raw, and it wasn’t until about 1.5 million years ago that we see evidence of humans using fire. (3) At first, they probably captured fire from naturally occurring fires that happened during lightning strikes. Eventually, they figured out how to make it themselves. We do not know if early use of fires was only for warmth of if they were using it for cooking as well, but we know that for around a million years all animals eaten by pre-humans was raw because they did not have fire before this time.
It wasn’t until about 300 to 400 thousand years ago that fire became a “significant part of the hominin technological repertoire”, as one research article put it. (4) It has been suggested that cooking food increased the available calories to our ancestors and therefore allowed for further evolutionary advances, however it has been shown that cooking of meat does not provide an advantage that would have furthered our evolution as far as increasing brain size. (5) Cooking may have allowed for the safer eating of plant foods by way of breaking down toxic compounds that made plants inedible for humans, but this would have only been done during times when animal foods could not be attained.
Fire did push our evolution in another direction though. It created a hearth. A place where humans would gather for warmth while they cooked and ate food. This would have laid the foundations for more complex social networks, cooperation, and language. It could be argued that these are the things that really made us human.
Regardless, humans and pre-humans have been cooking food for a long time, and meat has been the center piece of our meals. Even today, in most westernized countries the meal is centered around a meat and complimented by other foods. I am an advocate for a animal-based diet, but in this day and age how we process and cook meat is more important now than it ever has been in the past.
What makes it more important than ever before is the fact that we are bombarded with unnatural toxic chemicals on a daily basis. These are compounds that throughout our evolution we would have never come in contact with, and therefore our body has no use for them. One example of a compound our bodies find foreign is heavy metals. These are elements that were deposited deep in the earth way before humans, or any multicellular life, showed up. They were not present when our physiology evolved. It was only recently, in the industrial revolution, that we began to mine these materials out of the Earth and suddenly put our bodies in contact with them. Because of this our body does not know what to do with them and they can actually damage the body by interfering with metabolic processes.
Due to the amount of toxins we are exposed to, and the negative effects these toxins can have on our health, it is important to avoid as many of them as possible. You would go crazy trying to avoid them all, so it is important to avoid the ones you can control and not freak out about the ones you cannot control. One source of toxins we can all avoid are the toxins produced when we cook meat in certain ways.
Toxins produced while cooking meat were likely not a huge issue during our evolution. As we mentioned, much of the meat we ate was raw at first. But even when we began cooking it, and creating toxins in the process, these were likely one of the very few sources of toxins we were exposed to and our bodies had no trouble handling them through our antioxidant system. Today, toxins produced when cooking or curing meat are just one more toxin added to the toxin exposure pile. Fortunately, they are one that we have control over.
So what are the toxins produced in meat when it is processed or cooked? The main ones are called heterocyclic amines and polycyclic aromatic hydrocarbons. These are formed when amino acids, sugars, and creatines react when smoking meat or cooking it with high heat. Cooking above 320°F will induce this process. Many processed meats also have nitrosamines that are used to preserve the meat. So how bad are these compounds for our health?
Well, all three of the compounds mentioned above, polycyclic aromatic hydrocarbons, heterocyclic amines, and nitrosamines, have been shown to cause cancer. (6,7,8) It is very important to note that is the cooking and processing of the meat that creates these carcinogenic compounds, but meat itself is not carcinogenic. Aside from being weak epidemiological research, most of the articles that claim that meat causes cancer does not take into account the type of meat (processed or fresh) or the way the meat was prepared (burnt or not). We clearly see that these things matter, and it is irresponsible for these studies to claim that meat causes cancer without taking these factors into account.
To avoid these compounds, make sure you are only buying fresh meat from a good source. Aim for grass-fed and pastured animal foods. Do not buy processed meat like hot dogs or lunch meats. When cooking meat take care to char it as little as possible. My preferred way of cooking is to put the meat in a pan with some beef tallow and water, cover it, and let it simmer. This will give it some flavor from the fat and cook it without burning it. I realize that many people like the taste of the charred meat, but to me it is not worth adding more toxins to my toxic load.
Often times when I am done cooking it looks like the meat is not cooked because it doesn’t look burnt. But it is cooked, we are just so used to is looking burnt. I even had someone comment on a picture I posted on Instagram saying that they thought I was eating bacon raw because it didn’t have that crispy charred look to it. The less toxic ways to cook meat are simmering, sous vide (watch out for plastic toxins), light grilling, slow cooking, and broiling. More toxic ways of cooking meat are barbecued, charred, deep-fried, and microwaved.
Avoiding as many toxins as possible will help us decrease our levels of oxidative stress. This will help us not deplete Nitric Oxide in our bodies and will help maintain the health of the lining of our arteries. These are very important in preventing atherosclerosis and heart attacks. I have discussed the details on how that is in other blogs, here and here.
Cooking and preparing food is the least toxic way is a great strategy to be a happy and healthy keto/carnivore.
Stay healthy out there!
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