It is a nutritional plan based on the assumed ancient diet on wild plants and animals. (foodpyramid.com)
The paleo diet — also referred to as the caveman diet, the Stone Age diet and the hunter - gatherer diet — is a way of obtaining nutrition based on the presumed ancient diet of wild plants and animals that various human species habitually consumed during the Paleolithic era. (paleodietnews.com)
are all just ideas of what ancient diet would have been... I'm not sure when meat was introduced in the Bible but I wouldn't attribute sudden decrease in lifespan to just that. (elanaspantry.com)