When our human ancestors started eating meat, evolution served up a healthy bonus ­ the development of genes that offset high cholesterol and chronic diseases associated with a meat-rich diet, according to a new USC study.

Those ancestors also started living longer than ever before ­ an unexpected evolutionary twist…..

The research by USC professors Caleb Finch and Craig Stanford appears in Wednesday’s Quarterly Review of Biology.

“At some point ­ probably about 2 1/2 million years ago ­ meat eating became important to humans,” said Stanford, chair of the anthropology department in the USC College of Letters, Arts and Sciences, “and when that happened, everything changed.”

“Meat contains cholesterol and fat, not to mention potential parasites and diseases like Mad Cow,” he said. “We believe humans evolved to resist these kinds of things. Mad Cow disease ­ which probably goes back millions of years ­ would have wiped out the species if we hadn’t developed meat-tolerant genes.”

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