South African cavemen ate carbs, new research shows

Business Insider SA
San rock painting in the Drakensberg Mountains in
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  • Humans at Klasies River in South Africa knew how to forage for and cook potato-like tubers as early as 120,000 years ago. This is the earliest known evidence of humans roasting starches.
  • Cooking starches made the glucose in them more easily digestible, and is thought to be an important advance in human development.
  • Knowing where to find underground tubers could have helped modern humans to migrate inland. 
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Modern humans in South Africa roasted and ate potato-like tubers as early as 120,000 years ago, according to new research. This is the earliest evidence of this behaviour and the latest revelation to come from the Klasies River archaeological site in South Africa.

Klasies River, a collection of caves on the Eastern Cape coast, is an important archaeological site that has provided evidence of modern human behaviour in the Middle Stone Age, such as collecting shellfish and making tools.

Today, our diets are up to 80% starch, but there is limited information on when this began. “We needed energy to create bigger brains and babies, to make the bigger bodies and limbs, [humans] needed good quality protein and a lot more energy that we had previously thought,” says Cynthia Larbey, an archaeologist at the University of Cambridge and lead author on the paper.

This is why starches are important: by cooking them, these starchy plants would have provided pre-formed glucose, which greatly increased the energy available to early humans’ brains, red blood cells, and developing foetuses, the international team of authors write in their paper, published in the Journal of Human Evolution.

The researchers excavated and identified fire hearths from the site, which they then painstakingly sifted through and studied in microscopic detail, layer by layer. By looking at charred fragments under an electron microscope, they were able to identify cooked starches.

Following the release of the paper, Wits University’s Sarah Wurz, who is director of the Klasies River site, said the research showed that “early human beings followed a balanced diet and that they were ecological geniuses, able to exploit their environments intelligently for suitable foods and perhaps medicines”.

While there is evidence of humans eating roasted starches in the form of nuts, this is mainly in the Pacific region from about 70,000 years ago, Larbey says. “[Those sites] haven’t got this idea of digging for roots and tubers, and cooking them and that’s really quite important.” This behaviour is well-documented from about 50,000 years ago, but not as early as Klasies River suggests.

Not only is this evidence of modern human behaviour, but it would have enabled people to migrate, Larbey says.

These humans would have had to know how to identify these tubers from their leaves above ground, to know whether they were toxic, and when would be the best time to consume them.

“It was the way we were able to continue to feed ourselves as we moved and migrated,” Larbey says. “It was a skill to be able to find food as [humans] moved into different ecologies.” Hunting was more unpredictable than we could ever imagine, she explains.

She hopes to study inland archaeological sites for evidence of starch-roasting.

“In South Africa, and in South African archaeology, there is a wonderful acceptance that plants formed part of the hunter-gatherer diet. That isn’t accepted everywhere and [this] paper was important from that perspective.”

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