Scientists believe that eating sliced meat like bacon and other similar meats enabled our humankind to become a dominant species.
Boffins from Harvard University said it meant humans saved an average of 2.5 million chews a year, which meant our ancestors had more time to dedicate to focussing on other skills which helped us rise to the top.
Katie Zink, the first author of the study, said: “What we showed is that… by processing food, especially meat, before eating it, humans not only decrease the effort needed to chew it, but also chew it much more effectively.”
This ultimately led to smaller teeth, faces and guts which allowed important traits such as language to develop.
Daniel Lieberman, the Edwin M. Lerner II Professor of Biological Sciences at Harvard University, said: “With the origin of the genus Homo…we went from having snouts and big teeth and large chewing muscles to having smaller teeth, smaller chewing muscles, and snoutless faces.”
“Those changes, and others, allowed for selection for speech and other shifts in the head, like bigger brains.
Dr Lieberman added: “Chewing is one of the key characteristics of being a mammal.
“Most other animals, like reptiles, barely chew their food – they just swallow it whole.
“The evolution of the ability to chew food into smaller particles gave mammals a big boost of extra energy because smaller particles have a higher surface area to volume ratio, allowing digestive enzymes to then break food down more efficiently.”
The study, published in scientific journal Nature, points at our closest relatives, chimpanzees, which spend around 11 hours a day chewing their food, leaving them less time for hunting and gathering – a highly important aspect of early human civilisations.