I think you are not considering that before the domestication of plants, even if "food was growing around you all year long", it had low caloric content. The ke

I think you are not considering that before the domestication of plants, even if "food was growing around you all year long", it had low caloric content. The key measure is the cost of getting them calories. There are rough thresholds that almost guarantee that you may forever survive but never thrive.