If early humans had been vegans we might all still be living in caves, Swedish researchers suggested in an article recently published in the journal PLoS ONE.

When a mother eats meat, her breast-fed child’s brain grows faster and she is able to wean the child at an earlier age, allowing her to have more children faster, the study concludes. That provided a distinct competitive advantage for early humans when limited resources and a small population made it difficult for them to thrive.