The Klasies River Cave.
The Klasies River Cave. Courtesy Wits University

Starches have been dietary staples for even longer than seemed possible. For the first time, archaeological evidence confirms that humans have been roasting and eating plant starches for up to 120,000 years—that’s more than 100,000 years longer than we’ve been able to farm them.

An international team of archaeologists identified traces of prehistoric starch consumption in the Klasies River Cave, in present-day South Africa. Analyzing small, ashy, undisturbed hearths inside the cave, the researchers found “fragments of charred starch plant tissue” ranging from around 120,000 to 65,000 years old, making them the oldest known examples of starches cooked and eaten by humans. The team recently published its findings in the Journal of Human Evolution.

The findings do not come as a complete surprise, but rather as welcome affirmation of older theories that had lacked the corresponding archaeological evidence. In a press release, the lead author Cynthia Larbey of the University of Cambridge said that there had previously only been genetic and biological evidence to suggest that humans had been eating starch for this long. This new evidence, however, takes us directly to the dinner table, and so supports the hypothesis that starch digestion genes evolved as a specific “adaptive response to an increased starch diet.”

Cynthia Larbey points to a 65,000-year-old hearth at the cave.
Cynthia Larbey points to a 65,000-year-old hearth at the cave. Courtesy Wits University

Co-author Sarah Wurz, an archaeologist at the University of Witwatersrand in South Africa, said that the starch remains show that these early humans were “ecological geniuses” who could “exploit their environments intelligently for suitable foods and perhaps medicines.” And as much as we all still crave the rhizomes and tubers—think starches such as ginger and potatoes—that these cave communities were grilling up on their foot-long hearths, they knew well enough to balance their diets as best they could, with protein and fats from local fish and other animals.

This research is part of an ongoing investigation into how Middle Stone Age communities interacted with and made use of plants and fire. The investigation dates back to the 1990s, when the archaeologist Hilary Deacon first suggested that these hearths contained charred plants. (At the time, the proper methods to examine the residue were not yet available.) We now know not only that Deacon was right, but also that human beings have always been undaunted in pursuit of their cravings. “Starch diet isn’t something that happens when we started farming,” said Larbey—it’s “as old as humans themselves.”

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