To remain at our current level requires tremendous physical labor and organization of process just to deliver the required nutrients to every person, every day (and we still fail to achieve 100% distribution). There is a base level of effort required to sustain our current state. To believe otherwise is foolish delusion.
If you supply your own nutrients and use no product of another, you may exempt yourself from the previous analysis. Otherwise, I suggest we figure out how to achieve the above with as little 'work-hours' as possible.