Archaeologists say they have extracted a wide variety of starch grains from stone tools found at an early Middle Pleistocene site in Israel. These include acorns, grass grains, water chestnuts, yellow water lily rhizomes, and legume seeds.
Examples of some of the plants recovered from Gesher Benot Ya’akov percussive tools, including the whole plant, the edible part, and the characteristic starch grains. From left to right: oak, yellow water lily, and common oat. Scale bars – 20 µm. Image credit: Hadar Ahituv & Yoel Melamed.
The 780,000-year-old basalt tools were found at the early Middle Pleistocene site of Gesher Benot Ya’aqov, located on the shores of the ancient Hula Lake.
They were examined by a team of researchers led by Bar-Ilan University’s Dr. Hadar Ahituv.
“Our research contradicts the prevailing narrative that ancient human diets were primarily based on animal protein, as suggested by the popular ‘paleo’ diet,” the scientists said.
“Many of these diets are based on the interpretation of animal bones found in archaeological sites, with plant-based foods rarely preserved.”
“However, the discovery of starch grains on ancient tools provides new insight into the central role of plants, particularly starchy tubers, nuts, and roots, which are rich in carbohydrates vital for the energy demands of the human brain.”
“Our study also highlights the sophisticated methods early humans used to process plant materials.”
The authors recorded over 650 starch grains on basalt maces and anvils — tools used to crack and crush plant foods from Gesher Benot Ya’aqov.
These tools, the earliest evidence of human processing of plant foods, were used to prepare a variety of plants, including acorns, cereals, legumes, and aquatic plants like the yellow water lily and now-extinct water chestnut.
They also identified microscopic remains such as pollen grains, rodent hair, and feathers, supporting the credibility of the starch findings.
“This discovery underscores the importance of plant foods in the evolution of our ancestors,” Dr. Ahituv said.
“We now understand that early hominins gathered a wide variety of plants year-round, which they processed using tools made from basalt.”
“This discovery opens a new chapter in the study of early human diets and their profound connection to plant-based foods.”
The findings also offer insights into the social and cognitive behaviors of hominins.
“The use of tools to process plants suggests a high level of cooperation and social structure, as the hominins operated as part of larger social groups,” the researchers said.
“Their ability to utilize a diverse array of resources from both aquatic and terrestrial environments shows a deep knowledge of their surroundings, much like modern humans today.”
“The discovery marks a significant milestone in the field of prehistoric studies and provides valuable evidence about the dietary habits of our ancient ancestors, offering new perspectives on human evolution and the development of complex societies.”
The research is described in a paper published this week in the Proceedings of the National Academy of Sciences.
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Hadar Ahituv et al. 2025. Starch-rich plant foods 780,000 y ago: Evidence from Acheulian percussive stone tools. PNAS 122 (3): e2418661121; doi: 10.1073/pnas.2418661121