i was being deliberately vague, because there's no easy answer to that
oh by the way precious metals has nothing to do with how you feed a population, you can still expend energy on mining just fine
electricity isn't much of problem, it's cars and gasoline that's the biggest problem
in any event i would have to say the food consumption of mexico and the united states is extremely wasteful, both these countries take way too much calories then is good for them
the earth has resources enough to hold a population of 45 billion people, even in the worst case, which is the U.S. you're still talking twice the normal expenditure, so that would mean you keep about 22 billion U.S. citizens alive. Now demographers estimate the population will never reach that level, but will stay at about 12 billion. It could be 11 billion depending on how quick the underdeveloped countries go through the demographic transition.
So claiming that the world is overpopulated or will get overpopulated is bull****.
This Malthusian population bomb theory, of their being overpopulation has already been proven false. People really should stop using it, because it is such sheer and utter nonsense.