There is no optimum human diet. We eat what we can find. Our entire history has been without grocery stores and most of it without farms. People live don potatoes and lichen, field mice and berries. Modern medicine would have diagnosed every single one of our ancestors as malnourished and in need of meds.
the problem is movement, we don't move anymore. We eat shit that is not food and we don't move.
https://www.youtube.com/watch?v=skRb-oND3qA 