Zimbabwe's situation is exacerbated by the seizure of white commercial farmland for landless blacks which has hit output, critics say, and hyperinflation and economic collapse.
West and southern Africa are largely at peace, making access relatively easy but in East and Central Africa's war zones, many of the neediest are out of reach.
New fighting in eastern Democratic Republic of Congo has left WFP unable to reach a third of 300,000 new displaced, while in Ethiopia's Ogaden region government restrictions and a crackdown on rebels are seen blocking aid and trade shipments.
"Populations in these areas are reportedly consuming wild foods and, in the most food-insecure households, slaughtering livestock -- their main source of income -- for consumption," said famine early warning service FEWS NET.
"If trade restrictions continue, these negative coping strategies will lead to destitution."
But while conflict continues to drive food shortages from Sri Lanka to Colombia, hunger is more often caused by deepening poverty.
"If our planet produces enough food to feed its entire population, why do 854 million people still go to sleep on an empty stomach?," the U.N. Food and Agriculture Organisation Director-General, Jacques Diouf, said in Rome.
Pope Benedict said the world should consider the right to food a universal right for all human beings, without distinction or discrimination.
Increasingly, aid workers say it is time to move beyond handing out food as crises bite. They say simply speaking, longer-term programmes could save money.
Aid group CARE International says its programmes in West Africa's Niger, aimed at reducing poverty and building sustainable agriculture, cost only around $30 a person -- half the price of providing food at the peak of a 2005 food crisis.
While some government donors are being won over to that idea, obtaining funding for sustainable development lacks the draw of an urgent emergency appeal.
"With an emergency response, it is very easy to say who you helped and where," Africa food security expert for CARE International UK Vanessa Rubin told Reuters.
"It is not that simple when you stop a crisis."
