Humans have been eating ‘processed’ food for much longer than you would think

Archaeologists say the idea that our ancient ancestors survived on nothing but meat – and that the “carnivore” fad diet somehow harkens back to those times – is a myth.It turns out that humans have been eating processed plant food for far longer than previously thought, and reaping a host of benefits as a result. The new research debunks the popular myth of “palaeolithic meat-eaters”, instead showing our prehistoric ancestors used diverse plant resources, storing and consuming ground nuts as well as cooked starchy tubers.Researchers reviewed a number of studies pointing to the early use of plant foods by prehistoric humans and discovered that “complex plant processing” was critical to the successful spread of our species across the planet.“We often discuss plant use as if it only became important with the advent of agriculture," said Anna Florin, author of the study published in the Journal of Archaeological Research.“However, new archaeological discoveries from around the world are telling us our ancestors were grinding wild seeds, pounding and cooking starchy tubers, and detoxifying bitter nuts many thousands of years before this,” said Dr Florin, an archaeologist from Australian National University.Researchers point out that the human body is not designed to optimally metabolise protein for energy. Our liver has a limited capacity to maintain levels of amino acids, the building blocks of proteins, in the blood. This means an an excessive carnivorous diet can pose the risk of “protein poisoning”.“This limitation sets an absolute ‘protein ceiling’ on human diets estimated at about 250-300 g per day,” they write.“Plant foods, therefore, do not only provide important nutrients and more bioavailable energy in the form of carbohydrates,” the study notes, “they provide necessary calories beyond protein.”Researchers found that early humans processed food on the southwestern shore of the Sea of Galilee, where they discovered over 150,000 fossils preserved after plant gathering and processing at the 23,000-year-old Ohalo II archaeological site.They identified the fossils that appeared exceptional for their abundance of charred grass grains, including wild cereals and several types of small-seeded wild grasses. Researchers also found evidence of plant processing practices, including “cooking, pounding, and grinding”.These processes allowed for nutrients and energy derived from plant foods to be more effectively “unpacked” and made available for digestion, as well as more palatable, they said.“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," Monica Ramsey, another author of the study, said. “Our species evolved as plant-loving, tool-using foodies who could turn almost anything into dinner.”