Global hunger, poor nutrition and obesity are costing the world trillions of dollars in health costs and lost productivity, according to a new report from the U.N. Food and Agriculture Organization (FAO). The FAO report says fighting hunger is not enough. Tackling the more complex problem of malnutrition calls for action across the entire food system, from farm to fork. About 870 million people worldwide are hungry, according to the FAO. But malnutrition is about more than just hunger.