Early humans relied on plant foods much more than expected

A new archaeological study argues that humans have always been plant processors, not just meat hunters. From Ice Age Israel to northern Australia, early people were grinding seeds, cooking roots, and taming toxic nuts long before farms existed.

The work pulls together nearly two million years of scattered evidence to tell one story of a deeply flexible diet.

The research comes from teams at the Australian National University (ANU) and the University of Toronto Mississauga (UTM), who reevaluated dozens of classic sites with fresh questions.

Early humans relied on plants

Modern paleo style diets often paint the past as a time when people mostly gnawed on big animal carcasses and skipped grains and starches.

Archaeological finds and human biology tell a more complex story in which plants quietly carried much of the energy load.

The work was led by S. Anna Florin, an archaeobotanist at the Australian National University in Canberra. Her research focuses on how ancient people used and processed plants in different environments.

In this new study the researchers describe humans as a broad spectrum species that has long depended on processed plant foods.

“We often discuss plant use as if it only became important with the advent of agriculture,” said Florin, whose work tracks plant use long before farming.

Earlier theories described a sudden turn toward diverse foods near the end of the Paleolithic. New evidence suggests that variety was normal rather than rare across much older periods.

Early plant kitchens

At Ohalo II in northern Israel, archaeologists reported tens of thousands of grass and cereal remains in a landmark paper. 

These deposits date to the late Paleolithic, a very old period of human history in the Stone Age. The remains were found beside grinding stones that still carry microscopic cereal starch.

At Madjedbebe in northern Australia, a team identified charred yams, palm pith, and pandanus nuts in a detailed analysis. 

Those plant fragments show that the earliest known Australians were pounding, grinding, and cooking tough resources to release the calories locked inside.

“This ability to process plant foods allowed us to unlock key calories and nutrients, and to move into, and thrive in, a range of environments globally,” said Monica N. Ramsey, whose research traces early food technologies.

Many of these tasks needed simple wooden or stone tools that often vanish from the record. Their absence in some places does not mean people ignored plants.

Steady energy in difficult conditions

People cannot survive for long on lean protein alone because the liver quickly reaches its limit for turning excess amino acids into waste.

A type of malnutrition known as “rabbit starvation” made explorers sick in a matter of weeks when fat was scarce and plant foods were limited.

A global survey of 229 hunter-gatherer groups found that most got more than half of their calories from animal foods. They still depended on plants for energy-rich carbohydrates.

Fat from animals and carbohydrates from plants gave early people steady energy in difficult seasons. That mix helped them survive long journeys and unfamiliar landscapes.

A long record of starch

Recent work shows that humans, Neanderthals, and Denisovans shared extra copies of the salivary amylase gene hundreds of thousands of years ago.

The salivary amylase – a starch digesting enzyme found in human saliva – shows a long record of starch use that fits the archaeological evidence.

These genetic patterns line up well with the archaeobotanical record, which documents the use of wild grasses, tubers, and fruits across several continents today.

Researchers see this combination of biology and behavior as evidence of a persistent plant-centered skill set.

Humans evolved to love plant foods

The noisy debate over what humans are built to eat often forgets that our bodies evolved with many plant foods and cooking methods.

“Our species evolved as plant-loving, tool-using foodies who could turn almost anything into dinner,” said Ramsey.

The real lesson from this research is that human diets have always been varied and inventive rather than tied to a narrow menu.

Varied cooking traditions shaped regional cuisines over many generations. Those traditions reveal how people adapted plant foods to local needs.

The study is published in the Journal of Archaeological Research.

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