The decision for humans to be either carnivorous or herbivores was made millions of years ago. It was not a decision based on the ideals of modern society, personal beliefs, or political motivation. The decision was made in a time when humans were simply mammals, with no societal complexities beyond surviving the trials of evolution. The incidental nature of evolution can make the difference between advancement and failure of a species; creating the greatest paradox in the debate over man’s modern consumption of meat. The fact is- we are no longer primates as a result of our distant ancestor’s change in diet. That change was the introduction of meat.
A recent article, Earliest Archaeological Evidence of Persistent Hominin Carnivory by Joseph V. Ferraro and colleagues, showed studies at an archaeological dig site in Kenya revealing the earliest evidence of man’s evolution into an omnivore. “Over the last several million years, the hominin gastrointestinal tract has evolved from a chimpanzee-like large-intestine-dominated configuration well adapted for digesting fruits and other plant parts (as well as the occasional small mammal) to a more carnivore-like small-intestine-dominated form well suited for extracting complex nutrients from animal remains.” Beyond the physiological adaptations of our digestive tract, they discovered evidence dating as far back as 2.6 million years ago that illustrated our ancestors’ use of tools for scavenging.
This was the beginning of man’s adaptation to becoming a predator. More importantly, this was the beginning of our evolution from primate to the intellectually advanced human. The interesting nature of the evolutionary process is the physiological response to behavioral aspects of a creature. Our carnivorous history can be directly linked to our adaptation beyond that of other primates; to the thing that makes us human. Our brain.
Meat is a food source higher in protein nutrients than anything that could be gathered from a plant, and as the Expensive-Tissue Hypothesis, (Leslie Aiello, 1995) explained, the evolved size of the small intestine in humans is directly correlated to the large and complex brain size. The smaller the intestinal tract, the more output of valuable nutrients to support the intricate and expansive human brain. Small intestine is indicative of a carnivorous/omnivorous diet, as large intestine is indicative of herbivorous diet. The evolved human digestive tract shows a clear natural predilection for an omnivorous diet, or as it started, a scavenging diet.
Humans do not have multiple stomachs like most herbivores or any evolutionary advantage designed to break down cellulose, which is the primary design of plant eating animals. The human digestive system is almost a complete failure when it comes to breaking down cellulose and B12. B12 is an essential vitamin to the survival of all mammals. There are only two ways for a mammal to receive B12; through the consumption of meat, as humans and other predators absorb their vital B12, or through the digestion of plants, which is only possible with specialized organs. We do not have rumens (an organ present in ruminant animals) or the ability to do “hindgut fermentation”.
The segueing from an herbivorous diet is what incited our ancestors to use their brains at all. Hunting was the first driving force as a species to create tools, language, and subsequently caused the pack mentalities that developed into societies. Eventually, we developed into what we are today. That is how meat made us human.