Fast and cheap. That's how we expect our food. But global demand is expected to double by 2050. Scarcity affects every continent. Riots and protests over food prices ripple across much of Africa, South Asia and Latin America. Even in the United States, food prices have soared recently. Marketplace, Marketplace Morning Report and Marketplace Money look at how we got to this point and how the world is coping with the prospect of not enough food.