Dirty 'kitchen' tools reveal that cavemen were grinding their own flour and preparing vegetables for meals at least 30,000 years ago, according to new research.
The discoveries represent the oldest evidence for flour preparation and plant food processing.
Since the techniques were already well established during the Mid-Upper Paleolithic Period, it's likely that modern humans, and possibly even Neanderthals, incorporated far more plant products into their diets than presently believed.
Cavemen were apparently expert cooks too, so enjoyment of tasty prepared food is not unique to modern times. It also boosted the diners' health.
"Cooking enhances digestibility and also the taste of starch is improved by cooking," says lead author Anna Revedin, adding that it also helped to fuel the active lifestyle of hunter-gatherers.
"We are quite convinced that flour enhanced their mobility capacity, since it ensured a good source of energetic food during their travels," says Revedin, a researcher in the Italian Institute of Prehistory and Protohistory.
She and her colleagues analysed mortar and pestle-type stones that were found at three sites: Bilancino II in the Megello Valley of Italy, Kostenki 16 at Pokrovsky Valley, Russia; and Pavlov VI in southern Moravia, Czech Republic.
Since modern humans as well as Neanderthals inhabited these regions, the researchers think it's possible that either or both groups had cooking know-how.
Flat bread and soup
The food preparation tools were found to contain the remains of starch grains from various wild plants, including cattail rhizomes, cattail leaves, moonworts, the ternate grapefern, lady's mantle, burdock, lettuce roots, rye, burr chervil root, parts of edible grasses, edible seeds and more.
Flour made from cattails - which tastes a bit like the plant's distant cousin, corn - seems to have been particularly popular.
"Our experiments suggest that it is possible to mix this flour with water to obtain a sort of flat bread cooked on hot stones," Revedin said. "It is also possible that the flour was used in a mixed soup."
She says this would have increased the "nutritional power" of basic meals common to nomadic populations.
Virtually all of the discovered cattails and ferns are rich in starch and, as such, represent significant sources of carbohydrates and energy, according to Revedin and her team.
The foods were chosen, they believe, due to the plants' proximity to campsites, their prevalence, their size and their appearance, with the latter referring to foods that must have been favoured due to years of tried and true eating experience.
These foods aren't on most menus today, she says, since they don't grow easily as crops, and are probably less productive than more common counterparts, such as cereals.
The team published their work in this week's issue of Proceedings of the National Academy of Sciences.
Meat and veg diet
Professor Erik Trinkaus, a physical anthropology researcher at Washington University, says people at that time, likely members of the Gravettian culture, were "very effective at exploiting lots of resources, making the oldest textiles, having elaborate burials and clothing, and producing a variety of forms of art."
Archaeologist Ofer Bar-Yosef of Harvard University says the described method of making flour is similar to what Australian Aborigines and early Israelis did, with evidence for their plant food processing dating to later times. He also does not rule out that Neanderthals prepared flour and cooked with veggies too.
Bar-Yosef hopes archaeologists will now pay more attention to residues embedded in grinding slabs.
"It will help us to create a balanced view of Palaeolithic diets of prehistoric humans," he says. "This may have an impact on suggestions made by nutritionists concerning a meat rich diet as a way for prolonging healthy life."