Wall paintings in Grotta Paglicci, Italy (Image: Stefano Ricci)

Going on the palaeo diet? Don’t put down your porridge just yet. Hunter-gatherers ate oats as far back as 32,000 years ago – way before farming took root.

This is the earliest known human consumption of oats, say Marta Mariotti Lippi at the University of Florence in Italy and her colleagues, who made the discovery after analysing starch grains on an ancient stone grinding tool from southern Italy.


The Palaeolithic people ground up the wild oats to form flour, which they may have boiled or baked into a simple flatbread, says Mariotti Lippi.

They also seem to have heated the grains before grinding them, perhaps to dry them out in the colder climate of the time. Mariotti Lippi notes that this would also have made the grain easier to grind and longer-lasting.

This multi-stage process would have been time consuming, but beneficial. The grain is nutritionally valuable, and turning it into flour would have been a good way to transport it, which was important for Palaeolithic nomads, she says.

Cereal fuel

To see the benefits of a plant-based diet, you only need to know that society has been largely fuelled by processed grains for the last 10,000 years, says archaeologist Matt Pope of University College London. “There is a relationship there to be explored between diet, experimentation with processing plant food and cultural sophistication.”

This is another example of the advances made by Europe’s Gravettian culture, which produced technology, artwork and elaborate burial systems during the Upper Palaeolithic era, says Erik Trinkaus at Washington University in St Louis, Missouri. “These people were described 15 years ago as ‘Hunters of the Golden Age’, and the details of that are still being filled out.”

Mariotti Lippi’s team hopes to continue studying ancient grinding stones to find out more about the Palaeolithic plant diet. Grinding stones go back a long way, says Trinkaus, and people may well have been pounding and eating various wild grains even earlier than 32,000 years ago.

“We’ve had evidence of the processing of roots and cattails,” but here we’ve got a grain, and a grain that we’re very familiar with,” says Pope. “If we were to look more systematically for ground stone technology we would find this is a more widespread phenomenon.”

Journal reference: PNAS, DOI: 10.1073/pnas.1505213112

Grinding stone from Grotta Paglicci, Italy (Image: Stefano Ricci)