"Today I am obliged to buy half the food I used to buy mid-last year," said Mami, a mother of five.
Kinshasa shopkeeper Abedi Patelli said prices rise when the exchange rate of Congo's currency falls. "But when our currency improves against the U.S. dollar, prices don't fall," he said. "They remain steady."
WFP spokesman Greg Barrow said poorer countries can suffer a "ratchet effect" that locks in price rises due to high transportation costs and limited competition.
"Prices dropped fairly dramatically toward the end of 2008 on international markets but we found prices remained relatively high in many local markets in developing countries," said Barrow.
Image: In this picture taken on May 18, 2010, vendors and customers occupy a wholesale fruit and vegetable market in Islamabad, Pakistan.