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When Did Humans Start Eating Meat?

By Liam McAuliffe Updated on

The answer to the question, “When did humans start eating meat?” is much more than a date on a timeline. 

It’s the beginning of the story of humanity as we know it. That’s right, without meat, there would be no you and me, no humans, period!

Our species’ ability to first scavenge, a then hunt the large animals (megafauna) that roamed the ancient savannah provided early humans with the perfect fuel to rapidly grow their brains. 

This meat-based fuel was not available to our primate ancestors, who ate edible leaves, fruit, and occasionally small prey. 

In this article, we’ll explore the question of when humans started eating meat, look at the role of meat in human dietary evolution, and discover what this can tell us about the role of meat in our modern diets. 

Table of Contents

Why Did Humans Start Eating Meat? 

Meat eating, like all evolutionary adaptations, is as much a story of “why” as “when.”

The story of human carnivory began before humans existed. We’re talking six million years ago. 

That’s when the earth entered a wet and warm period where the vast African grasslands called savannah became much more humid than they are today. Picture endless marshy expanses dense with edible leaves and fruiting shrubs. 

During this period, our primate ancestors migrated out of the tropical forests into the savannah, where they thrived on fruits and leaves for nearly three million years. 

Then the earth underwent another major climate shift that dried out the savannah. And once again, the year-round supply of edible vegetation disappeared. 

This drying period was a catastrophe for numerous species, while the ones who survived were forced to adapt in dramatic ways. 

The survivors included a number of species referred to as hominids or pre-human ancestors. 

These pre-humans adapted by learning how to scavenge the meat locked in the bones of large mammals that other predators had taken down. 

These bone meats, including bone marrow and brains, provide an abundance of saturated fats, cholesterol, minerals, and fat-soluble vitamins that constitute the perfect fuel for the rapid growth of our brains. 

Archaeologists have pieced together this story from the signs of butchery cut into ancient bones dating back 2.6 million years [1] [6]  

So, to answer the question of when humans started eating meat, we know that it was at least 2.6 million years ago. 


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We Became Human By Eating Meat

Though some small brained primates ate small, lean prey, it was the proto-human’s ability to harvest fatty meat of giant mammals known as megafauna that provided the surplus of nutrients that allowed the most energy-hungry organ–the brain–to undergo rapid evolutionary growth. 

chart of brain growth

As the brains of early humans bloomed, they soon became intelligent enough to make and wield sophisticated hunting tools and to organize into groups that would allow them to take down large prey themselves. [4] [5]

Then for nearly 2 million years until the dawn of agriculture only 10,000 years ago, humans thrived as hypercarnivorous apex predators who ate mostly fatty meat. 5

This might sound strange to us modern humans who were raised in a grain based culture where we’re fed a nutritional dogma preaching a “balanced.” “plant-based” diet. 

But from the perspective of caloric return, it wouldn’t make sense for our ancestors to waste energy gathering seeds and edible greens when you could harvest many thousands of calories from a single animal. 

collection of cave drawings depicting animals

Some context here is helpful. During the ancient Pleistocene, the world was teeming with truly giant animals. The larger the animal, the fatter it is. The fatter it is, the more calories it packs, since per gram fat has about twice as many calories as protein. 

chart showing relative fat content to animal size



And let’s remember that most plants are naturally poisonous and must have their poisons bread out of them in order to be safe to eat. Furthermore, there was no fire to cook tubers–the most nutrient-dense plants until around three hundred thousand years ago. 

So before this time, humans were happy to focus their efforts on hunting and eating mastodons that were twice as large as elephants, 1200-pound armadillos, and 2000-pound chinchillas.[3] 

megafauna animals

Source: Lifegate Daily

It’s also no coincidence that the agricultural revolution came at the end of the Pleistocene during a time when these giant animals were going extinct across the globe due to human hunting. 

Humans became such effective meat eating machines that we burned through our primary fuel source. Only then were we forced to settle down in many parts of the world and cultivate a far inferior food source–plant foods. 

The Legacy of Meat Eating

It is no wonder that all of the “essential” nutrients that humans need are found in meat. They are essential to us not necessarily because of the nutrient itself but because humans evolved in relationship to food sources that provide these nutrients in abundance. 

As we consumed them in abundance over long periods of time our bodies built apparatuses that relied on them. 

The nutrients that built our massive brains and distinctly human physiology are the nutrients that maintain our brains and physiology. And they’re found primarily in meat, including

Our modern bodies reveal our genetic adaptations to eating lots of fatty meat over two million years. Here’s a rundown of our meat-based physiology.

  • We are unique among primates in that we store much more fat (as energy) on our bodies. The leanest version of a human is a male bodybuilder, who on average, has 200-300% more fat than other primates. 
  • Unlike other predators, humans can easily enter ketosis, a metabolic process that metabolizes fat into powerful energy molecules called ketones during mundane, calorically replete states. Most other animals need to be in starvation states. In other words, we’re adapted to eating a diet of fatty meat with very little carbs–the recipe for ketosis. 
  • Chimpanzees, who we split from 5 million years ago, have more than ½ of their digestive tract as the colon and cecum. These apparatus ferment plant fibers into fatty acids. In fact, primates and ruminants actually get around 70% of their nutrients from fat. It’s just that the fat is made in their bodies from plant fibers. Humans evolved away from this energy-intensive and inefficient ability when we learned to harvest the fat directly from other animals. The result is that humans have a much smaller colon and cecum. 
  • The stomach acidity of humans is much higher than even other carnivores and equivalent to various scavengers.3 This adaptation allowed humans to kill off pathogens in scavenged meat and large kills that could take days or even weeks to devour. 
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Lose the Meat Gain Disease

We know that humans started eating meat over 2.5 million years ago and relied on it for the majority of our calories until only 10,000 years ago. So what happens when we swap meat for grains, vegetable oils, and other industrial plant foods? 

We get sick and die from diseases related to metabolic disorders and chronic inflammation, including [17]

  • Heart disease
  • Cancer
  • Diabetes
  • Osteoporosis
  • Neurodegenerative disorders

These diseases were virtually non-existent for our hunter-gatherer ancestors and had been held at bay by the few remaining meat-centered diets of traditional non-western societies.3  [10] 

Yet, in Western societies consuming a modern grain-based diet, they are on the rise.[17]

chart showing increase in the disease of civilization

When Did Humans Start Eating Meat? The Bottom Line

Humanity came into existence when proto-humans began focusing on eating meat nearly three million years ago. 

Humans are the direct result of meat eating and can be said to have started eating meat as soon as we became differentiated from our ancestors around 2.6 million years ago. 

Our modern bodies have retained core metabolic processes that are tuned over millions of years to the specific nutrition provided by meat, including various essential macro and micronutrients. 

Yet our modern grain-based food systems and sedentary lifestyles create internal and external habitats that our bodies are not in accord with our metabolic and physiological needs. Humans have proved incredibly adaptable, but there’s a difference between adapting and thriving. 

And adapting to the grain based system is a root cause of the diseases of civilization–the largest causes of death worldwide. Each of these is related to chronic inflammatory disorders fueled by poor diet. 

Cutting out processed foods and increasing your intake of fresh meat may be a way to bring your physiology back into alignment with our ancestral legacy.

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