Your Paleo Practitioner
Our Ancient World, Human Evolution & The Paleolithic Era
Humans belong to a genus called hominin and they date back during the Pliocene era to about 2.5 million years ago. Paleo-anthropological records from sites in Kenya, Africa have been found to date back 1.76 million years. There, human remains were found to have the key adaptations of enlarged brains, tooth size reduction, smaller gut (seen in meat-eaters) and increased body size. This is also one of the oldest sites of evidence that hominins used tools to butcher their prey. It was from the understanding of the remains from this era that we believe our ancestors took the path of evolution different from other primates. This also has led us to improved insight of what early humans ate.
According to Charles Darwin, “adaptation is the end product of natural selection”. Therefore, adaptation results in reproductive success for future generations. Nutritional requirements for any organism is determined by the evolutionary expression of genetics. Adaptation of a trait provides a distinct advantage in the performance of a behavior for an organism which can insure the success of a species. Human adaptation to a meat centered diet was observed with the examination of the dental remains of early humans. It has been suggested that molars, used for grinding coarse and fibrous foods, must be designed for grains. This is unlikely, as grains did not compose any significant percentage of the diet of early humans. Instead it is believed that these crowned molars were used for nuts, seeds and the very fibrous vegetables and leaves common in these early eras.
Humans have evolved to be a hybrid of carnivores and herbivores as we are suited to both meat and vegetables. It is believed that human amylase production evolved in response to eating fibrous tubers. This adaptation preceded grain consumption by millions of years. Humans also have a gall bladder to secrete bile to aid in lipid (fat) digestion as well as other digestive enzymes produced in the pancreas to digest carbohydrates, fats and proteins. This physiologic evidence supports a diet high in animal protein and is further substantiated by the discoveries of stone hunting tools.
It was the development of stone tools which allowed the actual pursuit of animal protein which eventually led to humans developing larger brains. The earliest evidence that our descendants used stone tools was almost 2 million years ago with Homo erectus in Africa. These tools could never have come about without the advanced brain of our species. Without animal protein in the diet, we likely would never have taken this path. This new food source provided the critical nutrition for subsequent human species. Animal protein is a food source that is available year round, and in every climate on the Earth. Stone implements were also used for protection and from the inherent risks associated with predatory behaviors. Interactions with large game is a dangerous proposition. However, the risks were worth it as this new food source provided the long chain fatty-acids critical to human brain development.
The human brain is composed of 60% lipids – mainly phosphoglycerides and cholesterol. These lipids are rich in long chain fatty-acids, many of which are considered to be “essential”. Essential fatty-acids are those which our body cannot manufacture and therefore must be consumed in the diet. Protein from animal sources are distinguished by their amino acid content. These are the building blocks of proteins. Out of the 190 amino acids, only twenty are necessary in order for humans to synthesize proteins. Out of these twenty, eight are considered essential and they are easily supplied from a diet rich in animal protein. Our inability to synthesize all the proteins we need is likely an evolutionary adaptation to preserve energy when humans began hunting two to three million years ago.
A Paleolithic lifestyle carries with it the risks associated with coming into close proximity to large game as well as other predators. Although it is probably true that humans from the Paleolithic era did not live long, it was not due to disease as is commonly seen in modern man. Early farmers had short life spans also, likely due to eating the poor quality food and subsequent nutritional deficiencies that plague those who eat a largely vegetarian, grain based diet. Hunter-gatherers may have had short lives compared to modern man but it was not due to chronic disease. Lifespan was probably cut short mainly due to injury and infection. Early man was also exposed to the elements of extreme weather including wind, rain, snow and sun. Women often died in childbirth and child mortality was high. If food was scarce, starvation was not uncommon. Murder was also a frequent cause of death.
It is widely believed that the human genome in modern man is basically identical to the Homo sapiens living 40,000 years ago. During the mid-20th century, there were many anthropologists that conducted studies on indigenous cultures alive on the plant. At that time there were over 220 native tribes. From these studies, we know that eating a largely Paleo diet can result in a long and healthy life. Many of the members of these cultures were found to live well into their 60’s and 70’s with virtually no diseases that plague the civilized world. It is largely the natural diet that was the basis for the health of the members. Therefore, it is logical to believe that if we try to mimic the diet and lifestyle of our ancient ancestors, we can reduce or eliminate the chronic diseases associated with our modern civilization.