It's reasonable to speculate that humans aren't suited to our modern lives, and that our health, our family lives, and perhaps our sanity would all be improved if we could live the way early humans did. Our bodies may have been better suited to how we spent the first 99% of our existence, the claim goes. In short, we have what the anthropologist Leslie Aiello, president of the Wenner-Gren Foundation for Anthropological Research, called "paleofantasies."
There hasn't been such a level of ancestral fantasizing in pop culture since Henry D. Thoreau hypocritically used modern tools and modern clothes and the wealth of a middle class family to supposedly get back to nature.
The paleofantasy is more elaborate because it supposes that we humans, or at least our protohuman forebears, were at some point perfectly adapted to our environments - we were in harmony. The 'know just enough biology to be wrong' contingent accepts this erroneous idea of evolution nature and its corollary that are we were good at things we had to do back in the Pleistocene so we should all go back no-cook diets and barefoot running.
It's also completely wrong, the way that kernels of interesting insight turn into goofy fad diets always go wrong.
Read more: Misguided Nostalgia for Our Paleo Past By Marlene Zuk, The Chronicle of Higher Education