The increase in the number of calories that are available per person is because of modern technology in the farming and food production industries. The increased availability of oil, copper, gold, silver, iron, aluminum, lead, zinc, etc., is also because of better technology that was developed by private industry. And Paul Ehrlich's claim that overpopulation causes poverty is utter nonsense. Africa has the best natural resources of any continent, and most of the countires in Africa have relatively low population densities. But Africa has the poorest people in the world.
Japan is much more densely populated than Africa, and Japan has almost no natural resources.
But Japan is one of the richest countries in the world. The hunger in Africa has everything to do with political factors. There is no link between overpopulation and poverty. Today the world has more people than ever before. And today the average person in the world has more food, more clothing, more housing, more medical care, more wealth, more material possessions, and a longer life expectancy, than ever before.