There are interesting elements to at least the concept. One of the things I've liked from Michael Pollan is how he's pointed out how our dietary systems might be able to adapt to handle a lot of the processed foods that now surround us. But evolution and adaptation cannot happen in a single generation, as it's really only been some 20-30 years where much of the world diet went to hell. Maybe in 100 years+ after lots of premature deaths and disease we'd weed ourselves out for the natural selection to survive eating that crap. But we're nothing close to that now.
On the other side, you could say that it's in the human DNA to properly consume and process foods that were familiar to us before the Agricultural Revolution, but that is so, so long ago I would even be hard pressed to believe that today we could still digest half the stuff we ate then.
Not only that, but our physiology has completely shifted and adapted since back then. No longer are we working 15x7 to plow fields through manual means anymore. We lead mostly sedentary lives with the occasional gym excursion to trick our bodies that we're still living a physical existence.
