This incredible story shows how well nature can provide to you, if you know what you are doing...and shows how far away from nature we actually have strived, since most of the users here (myself included), would probbaly have died of diarrhea after having eaten the first plant.
You can learn however and it's fascinating how much edible stuff grows around you. My gf knows quite a bit about it and at every hike she chews on some seemingly random weed along the way.