From Hunters and Gatherers to Farmers: The Transformation of Human Nutrition
Humans have relied on a wide variety of food sources throughout their evolution, contributing to species survival in different nutritional environments. Early humans, in particular, adapted to local food supplies: the Inuit primarily relied on fishing and hunting, while peoples in tropical regions mainly consumed plant-based foods. As early as 2 million years ago, early humans such as Homo rudolfensis and Homo habilis used stone tools to butcher carcasses and process animal foods. About 1.8 million years later, Homo erectus discovered fire, which enabled the processing of raw foods like plants and meat. This marked a transformation from scavenged or hunted animals to edible products. Anatomically modern humans, Homo sapiens, emerged around 300,000 years ago in East Africa and spread globally about 60,000 to 80,000 years ago. During this time, humans lived as hunters and gatherers, and their diet varied by season and geographic conditions. This diet was not always balanced and could be explained by factors such as energy density, fiber content, and fat content. The human body had 300,000 years (roughly 12,000 generations) to adapt to these food compositions.
With the onset of the agricultural revolution around 10,000 years ago, food intake changed fundamentally. While our ancestors were already gathering grains and starchy foods, advancements in farming led to a significant increase in both plant and animal food consumption. In the Neolithic period (11,500 to 3,600 years ago), wild animals like sheep, goats, pigs, and cattle were domesticated, becoming household and farm animals.
The historical progression highlights that humans and their ancestors are omnivores, with plant-based foods dominating throughout evolution. This is still evident in the anatomical and physiological features of humans today, which have barely changed since 2.5 million years ago. The proportions of the stomach, small intestine, and colon, along with the size of individual digestive segments, suggest a mixed but predominantly plant-based diet. In comparison to carnivores and herbivores, carnivores’ stomachs make up about 70% of the total digestive tract, while herbivores have a digestive system twice as long. The development of molar teeth, showing wear patterns, and the lack of starch-digesting enzymes in saliva, also indicate a predominantly plant-based diet. Moreover, our limited ability to synthesize Vitamin C is another trait that became less relevant due to the regular consumption of Vitamin C-rich fruits and leaves in the past. In contrast, carnivores can produce Vitamin C on their own.
Genetically, food processing and metabolism play a crucial role, shaped by constant food supplies over millions of years. This condition persisted until the end of the hunter-gatherer era. However, the beginning of the agricultural era about 10,000 years ago provided little time for complete genetic adaptation to the "new food supply." This is particularly evident in the examples of lactose intolerance and milk-protein intolerance, which point to incomplete adaptation.
The brain is also a significant factor in the evolution of diet. A comparison of today's brain with that of a chimpanzee shows that our brain is three times larger. There are assumptions that the growth and development of the brain correlate with meat consumption. The brains of Neanderthals, who were vegetarians, were of similar size to our brains and possibly had comparable cognitive abilities.
In summary, human nutrition has evolved significantly over time, as reflected in our genetics and physiological predisposition.
Sources:
Carlberg, C., Klotz, L.-O., & Molnár, F. (2022). Nutrigenomik Gene und unsere Ernährung. Springer Spektrum.