A comprehensive approach to food security needs to include investments to promote income generating activities for the poor and thus improve their ability to purchase food. Importantly, the payoff from hunger reduction in terms of economic growth can be substantial. Throughout the 1990s, the value-added per worker, in countries where 2.5% of the population was undernourished, was 20 times higher than in countries where more than 35% of the population was undernourished. Sources: www.fao.org/wsfs,www.fao.org/wsfs/fbrum2050/wsJs-forum and www.oecd.org/agriculture. In more extreme cases, production zones might shift.