This is a really thought provoking article from Scientific American about ancient humans and their diet.
the article touches on a ton of things that have bothered me when I hear people talk about eating "Paleo" (I have no problem with people wanting to change their diets and eat healthy but I'm super bothered by the lack of specificity the word "Paleo" implies).
One of the things that infuriates me about the Paleo craze is that most people fail to realize that the Paleolithic era was one of the longest (or is the longest? I forgot) eras of human evolution and development. Spanned hundreds of thousands of years, over which I'm sure there was quite a wide range of foods that early humans relied on.
Furthermore, when people talk about "eating Paleo", they really do look at it from a very narrow (and generally a Western) view point. What people over there may have been consuming is vastly different from what people in other continents and in other environments may have been consuming. Ugh.
And, this article doesn't discuss it, but I get so irritated when people say stupid sh!te like "Well, cave men didn't get cancer/diabetes/morbidly obese". Yeah, well cave men didn't live past 40, so they wouldn't get cancer. And they didn't drive around in shiny little metal boxes to pick up obscene amounts of highly processed food analogues at the local Qwik-E-Mart so they wouldn't get diabetes or become morbidly obese, now would they? But, I see far fewer people abandoning their cars in favor of walking or running everywhere (or in favor of riding their bikes, which probably isn't Paleo, but a sh!te ton healthier than sitting in a metal box all day, eating drive through, before picking up hundreds of dollars of processed fake food. Oh, I guess I'm wearing my ranty pants today.)
But, I think it's wicked interesting that the article briefly discusses the role of gut bacteria in digestion and nutrition. It's kind of a new field with some super interesting research. For instance, there's some studies that are starting to show that gut bacteria may play a huuuuuuuuuuge role in mood and mood regulation. It's crazy fascinating to think that little critters that help break down our food may also be influencing our day-to-day ups and downs & ranty pants. I can try to find the studies I read, if people are interested.