I had a hard time understanding Paleo-diets when they first became popular. Wasn’t the Paleolithic period really long, and wasn’t there a large variation in hominid habitats? I recommend Paleofantasy for a nice scientific look at the Paleolithic era. A paper in Nature released today provides some direct evidence of diet from this era by sequencing plaque from the teeth of several Neanderthals, and reconstructing their microbiome. Advancing in sequencing techniques have opened up information that was unavailable before. Their examples show that the diet ranged from mostly meat in one individual to vegetarian in a sample from a different geography. And none of these paleo-foods, such as woolly rhinoceros, mouflon sheep, moss and tree bark are commonly available in today’s marketplace. New data is always interesting, and the investigators stretch their findings slightly to suggest that there was some ‘spit’ exchanged between Neanderthals and other early hominids. Exchanges like that could be one of the reasons we have ended up with Neanderthal DNA in our genome.