The diet of hunter-gatherers living in Morocco, between 13,000 and 15,000 years ago, contributed to tooth decay. The remains of 52 individuals were studied, and all but three suffered from tooth decay. The research — led by Dr. Louise Humphrey from the Department of Earth Sciences at the Natural History Museum in London, England — found that a diet heavily based on starchy food, including sweet acorns and pine nuts, was the cause. When the nuts were cooked, the sugars became sticky and more likely to remain on — and in — the teeth. The results were a surprise because it had previously been thought that tooth decay arrived with farming and an increase in food processing, 10,000 years ago.