If you think cooking and food processing is a modern phenomenon, think again, as scientists have found evidence, which suggest that early humans cooked their first hot meals more than 1.9 million years ago, much earlier than originally thought.

Researchers at Harvard University, who studied tooth sizes and the feeding behaviour of extinct hominids, monkeys, apes and modern humans, concluded that cooking was commonplace among Homo erectus, our flat-faced and thick-browed ancestors, which lived 1.9 million years ago.

“We see a dramatic shift in the tooth size of Homo erectus, which means it was likely responding to a history already of eating cooked and processed food,” said Chris Organ, an evolutionary biologist at Harvard.

“If you’re cooking your food you have many more hours of your day free, and you can spend those hours doing other things, since you don’t have to eat as much to get your daily requirements,” Mr. Organ was quoted as saying by LiveScience.

Processed food is much easier to chew and digest and since chewing breaks up the food it means more surface area is available from which the gut can absorb nutrients, Mr. Organ said.

The result means more available calories per serving and less gut time needed to digest those calories. The research, published in the journal Proceedings of the National Academy of Sciences, found that chimpanzees spent 10 times longer chewing and eating than humans do, 48 per cent versus 4.7 per cent of their days.

It also found that Homo erectus, which emerged in Africa around 1.9 million years ago, spent 6.1 per cent of its time eating, while the Neanderthals spent 7 per cent of their time feeding. Statistical analyses placed these chew times within the range of time spent chewing for humans.

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