What proportion of human history does the Paleolithic era actually represent? The Paleolithic period spans from roughly two million years ago, when the genus Homo first emerged, to about 10,000 years ago, when the dawn of agriculture ushered in the Neolithic era. In contrast, it took humanity a mere 10,000 years to transition from farming to using 21st-century smartphones. If we look at the numbers, the Paleolithic era accounts for 1,990,000 of those two million years—an overwhelming 99.5% of human history.
If humans had truly evolved to eat meat, our genetic makeup would have adapted after passing through the extreme conditions of the Ice Age, during which humans consumed animal flesh simply to survive. Much like true carnivores, our genes would have evolved so that consuming cholesterol-heavy foods would cause zero damage to our blood vessels. However, the stark reality that modern humans who consume large amounts of meat suffer heavily from vascular diseases like atherosclerosis, heart attacks, and strokes proves that our genes have not undergone such a change [1].
The popular modern "Paleolithic diet," which many assume to be inherently healthy, harbors a fundamental flaw. It fails to consider our ancestral eating habits prior to two million years ago, focusing only on the prehistoric era after the genus Homo appeared. To truly understand the genes that govern human nature, we must look past the last two million years—when humans began eating meat as an environmental adaptation—and look back as far as six million years ago to the very origins of humanity.
Genes Adapt Only Out of Necessity
In nature, true carnivores synthesize their own vitamin C internally, whereas herbivores must obtain it directly from their diet. Humans actually possess the genes required to synthesize vitamin C within our DNA, but they are entirely inactive. The reason is evolutionary efficiency: from the earliest stages of human history, our ancestors absorbed an abundance of vitamin C through plant-based foods. Consequently, there was no evolutionary pressure to waste energy synthesizing it internally [2].
Vitamin C cannot be found in meat, fish, milk, or eggs; it is uniquely abundant in fruits and vegetables. This is why carnivores are highly susceptible to vitamin C deficiency if deprived of whole prey, whereas vegetarians never face this issue. Because vitamin C is water-soluble, it is highly vulnerable to heat, meaning it is best consumed in its raw, natural state. Furthermore, because any excess intake beyond the daily requirement is promptly excreted in urine rather than stored, fresh fruits and vegetables must be consumed every single day.
Because modern human genetics remain virtually identical to those of our early ancestors, the chronic diseases plaguing society today do not stem from human nature. Instead, they are caused by the modernized, heavily processed foods that have developed rapidly over the last century [3].
When we scrutinize our dietary choices, our primary motivation is almost always the desire for a long, healthy life. Yet, the average life expectancy during the Paleolithic era was a mere 25 to 30 years. Even when accounting for harsh environmental variables, it is difficult to argue that Paleolithic eating habits provide a benchmark for optimal health [4]. Modern humans live longer and healthier lives, meaning there is no logical reason to mimic ancient survival diets. Instead, significantly increasing our consumption of unprocessed fruits and vegetables while boosting physical activity is a proven method for preventing chronic illness. It remains an undeniable fact that a westernized lifestyle—characterized by high meat consumption and physical inactivity—is directly linked to the surge in chronic diseases [5, 6].
We do not need to look all the way back to the Paleolithic era to find populations that live long, vibrant lives. They exist today, primarily among rural populations in Africa and Asia who maintain a heavily vegetarian diet. Among these communities, atherosclerosis—the specific arterial disease that triggers heart attacks and strokes—is virtually nonexistent. Diabetes, high blood pressure, obesity, and cancer are also exceptionally rare [7, 8].
Examining True Human Nature
What does human instinct actually tell us? If looking at a live lamb makes you instinctively want to eat it, then meat consumption is part of your biological nature. However, the vast majority of people look at a lamb and find it cute and lovable; they do not experience an instinctive urge to slaughter and consume it. If a meal required us to directly consume the flesh of a living animal, watching it bleed drop by drop, most individuals would recoil in horror. Similarly, when people spot animal roadkill, they do not salivate like true carnivores; instead, they find the sight distressing and look away.
What humans do respond to instinctively is sweet, vibrant fruit. Merely seeing it causes our mouths to water and triggers an immediate desire to taste it. This reaction demonstrates that innate human nature aligns closely with a fruit-based vegetarian lifestyle (frugivore), where the diet centers primarily on fruits. Nature provides fruits in a vast array of distinct flavors—apples taste like apples, strawberries like strawberries, oranges like oranges, and bananas like bananas.
But what about the actual flavor of meat?
When we visit an orchard, we can pick fruit and eat it right out of hand. Yet, no one walks into a butcher shop and willingly eats raw meat straight from the display case. Such an act is unthinkable unless you are a biological carnivore. In its raw form, the natural taste of meat is intensely fishy and unpalatable; without cooking, it is far too unappealing for humans to consume immediately.
Humans lack the biological capacity to tear and consume meat raw. Instead, we must alter it through heat, transforming it to suit our palate. Even then, we mask the natural flavor with plant-based seasonings, transforming it into dishes like seasoned short ribs or bulgogi. When we evaluate what we enjoy, it becomes clear that people often crave the flavor of the seasonings rather than the meat itself—and those seasonings are derived entirely from plants.
If individuals were forced to personally slaughter an animal before every meal, the majority would refuse. Human nature is fundamentally distinct from that of a carnivore. Paul McCartney, the iconic member of the Beatles, famously highlighted the hidden cruelty of industrialized farming by stating, "If slaughterhouses had glass walls, everyone would be vegetarian." Because modern commercial systems completely conceal the slaughter process, consumers remain disconnected from what happens before the meat reaches the dinner table. We have been conditioned to enjoy meat that has been heavily altered by fire, frying, and intense seasoning, but humans do not possess an instinctive drive toward raw flesh.
The Genetic Evidence of Our Biology
Ultimately, humans are animals, and understanding our basic biological instincts is essential because no one is exempt from their evolutionary nature. The mere capability to digest meat does not automatically classify humans as carnivores or omnivores. The foundational fact that increased meat consumption leads directly to an escalation in physical illness serves as the most definitive evidence that humans did not evolve to be meat-eaters [9, 10].
For context, human genes and chimpanzee genes share a 98.4% identity [11], and a chimpanzee's primary diet consists of 98% fruit [12]. Biologically, humans achieve optimum health metrics when fueled by a plant-based diet.
Despite these biological realities, proponents of modern low-carb trends frequently argue that humans are natural carnivores, and a receptive public often agrees simply because they enjoy the taste of meat. It is a highly concerning reality. Many of these individuals attempt to sustain their health using an array of synthetic nutritional supplements marketed directly on low-carb websites, entirely unaware that their core dietary philosophy is flawed.
The fact that meat consumption is widespread does not alter human biology. Any diet that actively clashes with your evolutionary design will eventually demand a physical price, manifesting as chronic illnesses like atherosclerosis, myocardial infarctions, strokes, and cancer. To thrive, we must eat in a manner that respects human nature. Our genes have not changed. It is my hope that consumers will look past the sophisticated marketing of those who sell dietary supplements while promoting low-carb, carnivore lifestyles.
Dr. Song Muh-oh is an orthopedic surgery and lifestyle medicine specialist.
References
1. K Milton. Hunter-gatherer diets—a different perspective. The American journal of clinical nutrition 2000;71(3):665-667.
2. IF Benzie, S Wachtel-Galor. Vegetarian diets and public health: biomarker and redox connections. Antioxid Redox Signal. 2010 Nov 15;13(10):1575-91.
3. H Pijil. Obesity: evolution of a symptom of affluence. How food has shaped our existence. The Netherland Journal of Medicine 2011;69(4):159-166.
4. M Nestle. Paleolithic diets: a sceptical view. Nutrition Bulletin 2000;25(1):43-47.
5. SB Eaton, M Konner, M Shostak. Stone agers in the fast lane: chronic degenerative diseases in evolutionary perspective. Am J Med 1988;84:739–49.
6. L Cordain, RW Gotshall, SB Eaton, SB III Eaton. Physical activity, energy expenditure and fitness: an evolutionary perspective. Int J Sports Med 1998;19:328–35.
7. AR Walker. Are health and ill-health lessons from hunter-gatherers currently relevant? The American journal of clinical nutrition 2001;73(2):353-354.
8. WC Roberts.The cause of atherosclerosis. Nutrition in Clinical Practice 2008;23(5):464-467.
9. R Kay. Diets of early Miocene African hominoids. Nature 1977;44:628–630.
10. K Milton. Nutritional characteristics of wild primate foods: do the diets of our closest living relatives have lessons for us? Nutrition 1999;15:488–498.
11. DongA Science https://m.dongascience.com/news/8338
12. Wikipedia https://ko.wikipedia.org/wiki/%EC%B9%A8%ED%8C%AC%EC%A7%80#
