For millions of years, humans have evolved to survive and thrive on a diverse yet specific range of foods. The diet of our earliest Homo sapiens ancestors—those who lived around 300,000 years ago—was shaped by evolutionary pressures, climate changes, and anatomical adaptations. But what exactly did they eat? How do we know? And what does this mean for what we, as modern Homo sapiens, are designed to consume? Let’s explore exactly this in ‘The Diet of Early Humans & How This May Help Our Health.’
Through archaeological findings, fossil evidence, and genetic analysis, we can piece together a remarkably detailed picture of what our early ancestors ate—and how it compares to the modern diet.
The Evidence: How Do We Know the Diet of Early Humans?
Understanding the diet of early Homo sapiens requires analysing multiple sources of evidence, including:
- Fossilised bones and teeth: These show wear patterns and chemical traces that reveal the types of food consumed.
- Stomach contents and coprolites (fossilised faeces): These provide direct evidence of consumed food.
- Isotopic analysis: Examining the ratio of certain elements in bones can indicate plant or animal-based diets.
- Comparative anatomy: By studying our digestive system and teeth, we can infer what types of food we evolved to process.
- Genetic evidence: Our DNA, particularly in relation to close primate relatives like chimpanzees, offers clues about ancestral diets.
Archaeological digs in Africa, the birthplace of Homo sapiens, have yielded vast amounts of food remains, stone tools, and even microscopic food particles trapped in ancient teeth, helping us reconstruct the menu of our early ancestors.
What Did the First Homo Sapiens Eat?
1. Meat: The Staple of Early Human Diets
One of the strongest pieces of evidence supporting meat consumption is the presence of cut marks on animal bones found at archaeological sites. Homo sapiens were not just scavengers but skilled hunters, using stone tools and later fire to process and cook meat.
Meat provided a dense source of calories, essential amino acids, and fat – critical nutrients that fueled brain growth and development. The shift towards a meat-heavy diet is believed to have supported the expansion of our large, energy-hungry brains.
2. Fruits and Nuts: Seasonal and Nutrient-Rich
Despite a strong reliance on meat, early humans also ate fruits, nuts, and seeds. Fossilised dental plaque has revealed traces of wild figs, tubers, and berries. These foods provided vitamins, minerals, and antioxidants but were only available seasonally, meaning early humans did not eat them year-round.
Chimpanzees, our closest relatives, also consume fruit as a major part of their diet, but the amount available to early humans varied based on climate and geography.
3. Roots and Tubers: The First “Carbohydrates”
Starchy underground tubers, such as yams and wild potatoes, were an important source of energy. However, early humans did not eat them in the same way we consume modern carbohydrates. These tubers were fibrous, tough, and required extensive chewing. Unlike today’s processed carbohydrates, they were slowly digested, preventing sharp spikes in blood sugar.
Cooking tubers helped make their nutrients more accessible, and evidence of charred plant remains suggests early humans roasted some of their food.
4. Low Carbohydrate Intake Compared to Modern Diets
Unlike today’s high-carb, grain-based diet, early humans consumed very few refined carbohydrates. Grains such as wheat and rice were not cultivated until the advent of agriculture, around 10,000 years ago. While some wild grains were occasionally eaten, they were not a dietary staple.
This suggests that humans evolved to function on a diet low in processed carbohydrates, relying instead on proteins, fats, and fibrous non-starchy plant foods.
What Does Human Anatomy Reveal About Our Diet?
1. Long Digestive Tracts: Built for Diverse Diets
Humans have relatively long digestive tracts, a characteristic of omnivores. This suggests our ancestors consumed a mix of animal and plant foods. However, compared to herbivores like cows (which have multi-chambered stomachs for breaking down cellulose), our guts are relatively short, indicating an adaptation for digesting protein and fat more efficiently than fibrous plants and wheat.
2. Molar Teeth: Designed for Meat and Plants
Our teeth provide crucial insights into our evolutionary diet. The presence of both sharp canines and broad molars suggests Homo sapiens evolved to process both meat and plants. The molars were used for grinding fibrous tubers and nuts, while the sharper teeth helped with tearing meat.
3. Genomic Similarities to Chimpanzees: What They Tell Us
Chimpanzees, our closest genetic relatives, consume a diet primarily composed of fruits, nuts, leaves, and occasional meat. However, the key difference is that humans evolved with a greater reliance on animal protein and fat. This is evident in our higher tolerance for fats and our ability to digest cooked foods more efficiently.
While our digestive enzymes and gut bacteria resemble those of other primates, our ability to metabolise fats and proteins suggests we are designed to eat a more nutrient-dense diet than chimpanzees.
Counter-Argument: Are Humans Actually Designed for a Plant-Based Diet?
Some researchers and nutrition experts argue that humans are best suited for a predominantly plant-based diet rather than the high-protein, low-carbohydrate diet associated with our evolutionary past. Their reasoning includes:
- Gut Microbiome and Fibre Fermentation
- Studies show that humans have a diverse gut microbiome that thrives on plant-based foods. Our colons contain bacteria that break down fibre into short-chain fatty acids, which provide energy and support metabolic health.
- Herbivorous and omnivorous primates, including gorillas and chimpanzees, consume large amounts of plant matter, suggesting that high-fibre diets are more natural for primates, including humans.
- Health Risks of High Meat Consumption
- Some epidemiological studies link high meat consumption – especially processed and red meats – to increased risks of heart disease, colorectal cancer, and other chronic illnesses. (These studies, however, can show correlation but not causation). Some researchers argue that early human diets were lower in meat than commonly assumed.
- The World Health Organization (WHO) has classified processed meats as carcinogenic and red meat as a probable carcinogen, raising concerns about diets rich in animal protein.
- Longevity and Plant-Based Diets
- Blue Zones – regions where people live the longest and healthiest lives – are characterised by high consumption of whole plant foods, such as legumes, vegetables, fruits, and grains, with minimal animal products.
- Studies on longevity show that plant-based diets reduce inflammation, support cardiovascular health, and improve insulin sensitivity, suggesting that they may be more aligned with human health than a heavily animal-based diet.
- Evolutionary Adaptation to Agriculture
- Some researchers argue that humans have adapted to grains and higher carbohydrate intake over the past 10,000 years since the advent of agriculture. Lactase persistence in certain populations and genetic adaptations to starch digestion (e.g., increased copies of the amylase gene) suggest an ability to thrive on a higher-carb diet.
Conclusion of the Counter-Argument: While early Homo sapiens may have eaten meat, some modern evidence suggests that humans can thrive on plant-based or high-carbohydrate diets, which may even be preferable for long-term health.
Rebuttal: Why an Ancestral Diet Still Seems to Make the Most Sense
While the above arguments highlight important considerations, they seem to overlook key aspects of human evolution and biology. Here’s why an ancestral diet – rich in animal protein, healthy fats, and fibrous plants – may remain the most aligned with human physiology (according to the available research):
1. Gut Microbiome: Humans Are Not Herbivores
- While fibre is beneficial, humans do not have the specialised digestive tracts of herbivores like cows or gorillas. Our colons are much shorter, and our stomachs produce high levels of hydrochloric acid, which is characteristic of carnivores and omnivores designed to digest meat efficiently.
- The ability to ferment fibre in the colon is present in many omnivorous species, including pigs, but this does not make humans natural herbivores. Our gut is appears to be built for a combination of plant and animal foods.
2. The Meat-Health Controversy: Correlation vs Causation
- The claim that meat increases disease risk is largely based on epidemiological studies, which can show correlation but not causation. Many of these studies fail to account for confounding factors, such as processed food consumption, sedentary lifestyles, and smoking, which are common in populations that eat high amounts of processed meat.
- Hunter-gatherer societies that consume high levels of animal protein, such as the Inuit and Maasai, historically had low rates of heart disease and metabolic disorders – contradicting the idea that meat inherently causes health problems.
3. Longevity and Blue Zones: A Misleading Picture
- While Blue Zones emphasise plant-based diets, these populations also engage in daily physical activity, social cohesion, and low-stress lifestyles, all of which contribute to longevity.
- Many Blue Zone diets do include animal products, such as fish, dairy, and eggs. The Sardinians, for example, consume a high-fat diet that includes cheese and meat, and the Okinawans traditionally ate a higher percentage of animal protein than is often reported.
4. Evolutionary Adaptation to Agriculture: 10,000 Years is Not Enough
- While some human populations have adapted to specific agricultural foods (e.g., lactose tolerance in dairy-consuming cultures), this represents a relatively recent change in evolutionary terms. The majority of human evolution occurred in the pre-agriculture (farming) era, meaning our metabolic systems are still largely adapted to a hunter-gatherer diet.
- Many modern health issues, such as obesity and type 2 diabetes, became prevalent after the widespread consumption of grains, processed carbohydrates, and industrial processed seed oils (canola, cottonseed etc.), further suggesting a mismatch between modern diets and human biology.
What Are Humans “Designed” to Eat?
Given millions of years of evolution, according to the available evidence, the diet on which we evolved over millions of years appeared to be neither entirely carnivorous nor purely plant-based. Instead, the evidence suggests that early Homo sapiens thrived on a diet that included:
✅ Animal protein and fat (meat, fish, eggs)
✅ Fibrous vegetables and tubers (not modern processed grains)
✅ Nuts and seasonal fruits (low in sugar compared to modern fruit species)
✅ No refined carbohydrates (grains only became a staple following the agricultural revolution some 10,000 years ago)
This diet aligns closely with what is often referred to as an “ancestral diet,” such as the Paleo diet, which emphasises whole, unprocessed foods.
Conclusion
According to the available research, modern humans do not appear to be well-adapted to the processed, carbohydrate-heavy diets that dominate today’s food landscape, with foods such as bread, pasta, cereals and rice. Instead, our physiology suggests that we thrive on diets rich in animal protein, natural and unprocessed fats and fibrous lower carbohydrate plants – just as our ancestors did for hundreds of thousands of years.
By understanding what early Homo sapiens ate, we can make informed dietary choices that align with our evolutionary biology, promoting better health, sustained energy levels, and improved metabolic function.
Modern plant-based diets can seem healthy when carefully planned, but they require supplementation (e.g., B12, DHA, iron etc.), which is a clear sign that they are not the diet humans naturally evolved to consume.
Ultimately, the diet that aligns best with our evolutionary biology appears to be one that mimics our ancestral eating patterns, focusing on whole, nutrient-dense foods rather than the processed, high-carb diets that dominate today’s world.
Disclaimer: This article is meant solely for informational purposes and is not to be interpreted as medical advice or a replacement for professional healthcare from a registered medical professional. It does not aim to diagnose, treat, cure, or prevent any illness. Before making any dietary changes, beginning a new exercise program, or taking any supplements mentioned in this article, individuals should consult with a qualified and registered medical professional.
References
- Ungar, P. S. (2007). “Evolution of the human diet: The known, the unknown, and the unknowable.” Oxford University Press.
- Cordain, L. (2002). “The Paleo Diet: Lose Weight and Get Healthy by Eating the Foods You Were Designed to Eat.” Wiley.
- Eaton, S. B., & Konner, M. (1985). “Paleolithic nutrition: A consideration of its nature and current implications.” New England Journal of Medicine, 312(5), 283-289.
- Hardy, K., et al. (2010). “Starch granules, dental calculus and diet.” Proceedings of the National Academy of Sciences, 107(51), 20982-20986.
- Leonard, W. R., & Robertson, M. L. (1994). “Evolutionary perspectives on human nutrition: The influence of brain and body size on diet and metabolism.” American Journal of Human Biology, 6(1), 77-88.