Man's ability to digest starchy foods like the potato may explain our success on the planet, genetic work suggests.

This story on the BBC examines whether meat or, in fact, our ability to digest starch was the key player in humans' evolution of larger brains.

Meat does not appear to be the answer.

"Even when you look at modern human hunter-gatherers, meat is a relatively small fraction of their diet. "To think that, two to four million years ago, a small-brained, awkwardly bipedal animal could efficiently acquire meat, even by scavenging, just doesn't make a whole lot of sense."

This is the sort of answer veggies love but hold back a little. These are arguments about biology, they are not arguments about ethics or idologies, such as vegetarianism.

That we got our brain boost from starch does not prove vegetarianism right nor would that boost coming from meat prove it wrong. It merely tells us why are brains grew. Like wise, if it determined that rape is part of human adaptation it certainly does not legitimizes rape nor do adaptations for milk consumption give justification for inflicting the dairy industry on to sentient creatures.