If chimpanzees are our closest cousins, why didn’t they evolve like we did? German anthropologists say it’s the way we eat. From Wired:

In a study published yesterday in Public Library of Science ONE, a team of Max Planck Institute researchers compared gene expression in three groups of mice — one given a cafeteria-style human diet, another given the fruits and veggies consumed by chimps in zoos, and the last given McDonald’s takeout.

The chimpanzee diet produced thousands of changes in gene expression, especially in the mice’s livers. The same genes have been observed to differ between humans and chimps, who are otherwise nearly 99 percent identical at the DNA level.

If human and chimp diets triggered such changes in mice, figured the researchers, maybe a few million years of eating well are the reason why people aren’t still sucking termites off sticks.

“Some have proposed that it was our high-energy, high-protein and cooked diet that enabled us to fuel our big brains during our evolution,” said study co-author Mehmet Somel.

Being a meat and potatoes type a species allowed our brains to develop. So next time a vegan tries to tell you that meat is bad for you, don’t take it personally. It’s obvious that their brains didn’t fully develop.