About 11,000 years ago, humans made a major transition from hunting and gathering to farming. This change, known as the Neolithic Revolution, dramatically changed the way we eat.
For decades, scientists thought that pre-agricultural human groups consumed too much animal protein. However, the scarcity of well-preserved human remains from Pleistocene sites has always hampered analysis. So actually very little is known about the nutritional practices of that time.
I’m a PhD candidate studying this topic in Morocco, and I was part of a research team that uncovered some new insights into the Stone Age diet.
Using new research techniques, we found evidence that our Late Stone Age hunter-gatherer ancestors in North Africa had a predominantly plant-based diet thousands of years before the advent of agriculture.
Most studies of pre-agricultural populations have been conducted in European and Asian Paleolithic regions; Therefore, our understanding of nutrition in this period is largely based on findings obtained from these regions. Our knowledge was also limited due to the poor preservation of some materials in arid regions such as North Africa.
Our research changes this. It challenges the long-held belief that hunter-gatherers relied primarily on animal protein and adds to what is known about pre-agricultural diets in different regions.
Chemical traces on bones and teeth
Imagine being able to tell what someone ate thousands of years ago just by examining their bones and teeth.
This is possible thanks to a fascinating technique called isotopic analysis. Isotopes are tiny chemical markers of the food we eat that are stored in our bones and teeth. They can be stored for thousands of years. By studying these, we can obtain direct information about the diets of ancient people.
Since the 1970s, scientists have used stable isotope analysis to learn about the diets and lifestyles of ancient human groups by analyzing the collagen protein in their bones. Collagen is a protein found in connective tissue, skin, tendons, bones and cartilage. For example, carbon isotope analysis was used to detect corn consumption by prehistoric people in North America. Researchers have also used this technique to compare the diets of Neanderthals and early modern humans (homo sapiens) in Europe.
Together with an international team of scientists, I analyzed the teeth and bones of people buried in the Taforalt Cave in northeastern Morocco. The cemeteries were intentional. Researchers called this place a cemetery because of the orderly nature of the graves and the long period in which they occurred. The cave is one of the best-studied sites in northwestern Africa for the Paleolithic period. It is probably the oldest cemetery in North Africa. It has some of the oldest ancient human DNA in Africa, allowing scientists to characterize the genetic ancestors of humans in this region.
Human burials associated with the Iberomaurus culture were radiocarbon dated to between 15,100 and 13,900 years ago. Zoologists found that the population preyed on Barbary sheep and other animal species in their surroundings, such as gazelles, hartebeests and equids. Macrobotanical remains recovered from the site indicate that they also had access to a variety of plant species native to the Mediterranean region, including sweet acorns, pine nuts, oats, beans and pistachios.
We looked at isotopes of carbon, nitrogen, strontium, sulfur and zinc. Different foods leave unique isotopic “fingerprints.” For example, meat, plants, and seafood have different carbon and nitrogen isotope ratios, which helps us determine what types of foods people eat.
We also used cutting-edge techniques developed by one of my PhD supervisors, Klervia Jaouen, which involved applying zinc isotopes to tooth enamel. This method, combined with amino acid analyses, allowed us to further differentiate between plant and animal sources in the diet.
This innovative approach has given us a clearer, more detailed picture of what ancient diets were like, shedding light on how these people adapted to their environments long before they started growing crops.
The surprising diet of hunter-gatherers
We analyzed tooth enamel and bones from seven individuals and several isolated teeth from the Taforalt cave. Our analysis revealed something unexpected: Instead of a meat-heavy diet, isotope signatures showed a significant reliance on wild plants. We also found little evidence of consumption of seafood or freshwater foods; this was surprising given their proximity to water sources. Our research showed that while Iberomaurus consumed some meat, their diet relied heavily on wild plants, which they stored to ensure a year-round food supply.
One of the interesting discoveries we made was that a baby starts eating solid food at about six to 12 months of age. It looks like this baby was probably given plant-based foods like porridge or soup. This gives us a fascinating insight into how hunter-gatherers cared for their children in the past.
The findings also help explain why tooth decay is common among the people of Taforalt. They ate a lot of starchy foods that could lead to cavities, especially since there were no toothbrushes or good dental hygiene at the time. Plant parts get stuck between the teeth and cause decay, which leads to dental problems.
People who were mostly hunters would have to follow a nomadic lifestyle. However, at Taforalt, archaeologists found grinding stones that were probably used in plant processing. The extensive consumption of plants, as well as the use of the cave as a burial site, suggests that this population may have had a more sedentary lifestyle, taking advantage of the food resources already available in the environment.
Read more: Chemical traces on ancient West African pottery suggest a plant-rich diet
Looking forward
These findings challenge the conventional wisdom that the heavy reliance on plant-based diets began solely with agriculture. Iberomaurusians were consuming large numbers of wild plants 8,000 years before farming began in Morocco. This suggests that early humans were more adaptable and resourceful in their eating habits than previously thought. Understanding this helps us understand the complexity and flexibility of prehistoric human nutrition and how these dietary practices influenced our evolution and health.
Our work also shows how new isotopic techniques can give us detailed information about the diets of our ancestors and help us understand the basics of human nutrition.
This article is republished from The Conversation, an independent, nonprofit news organization providing facts and authoritative analysis to help you understand our complex world. Written by: Zineb Moubtahij, Leiden University
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Zineb Moubtahij received funding from the Max Planck Institute. It is affiliated with Leiden University.