Governments are urged to take action to help ease rising prices
The head of the UN World Food Programme has warned that the rise in basic food costs could continue until 2010.
Josette Sheeran blamed soaring energy and grain prices, the effects of climate change and demand for biofuels.
Ms Sheeran has already warned that the WFP is considering plans to ration food aid due to a shortage of funds.
Some food prices rose 40% last year, and the WFP fears the world's poorest will buy less food, less nutritious food or be forced to rely on aid.
Speaking after briefing the European Parliament, Ms Sheeran said the agency needed an extra $375m (244m euros; £187m) for food projects this year and $125m (81m euros; £93m) to transport it.
She said she saw no quick solution to high food and fuel costs.
"The assessment is that we are facing high food prices at least for the next couple of years," she said.
Ms Sheeran said global food reserves were at their lowest level in 30 years - with enough to cover the need for emergency deliveries for 53 days, compared with 169 days in 2007.
Among the contributing factors to high food prices is biofuel production.
Ms Sheeran says demand for crops to produce biofuels is increasing prices for food stuffs such as palm oil.
Ms Sheeran said governments needed "to look more carefully at the link between the acceleration in biofuels and food supply and give more thought to it".
The WFP says countries where price rises are expected to have a most direct impact include Zimbabwe, Eritrea, Haiti, Djibouti, the Gambia, Tajikistan, Togo, Chad, Benin, Burma, Cameroon, Niger, Senegal, Yemen and Cuba.
Areas where the WFP is already seeing an impact include:
Afghanistan: 2.5 million people in Afghanistan cannot afford the price of wheat, which rose more than 60% in 2007
Bangladesh: The price of rice has risen 25% to 30% over the last three months. In 2007, the price rose about 70%.
El Salvador: Rural communities are buying 50% less food than they did 18 months ago with the same amount of money. This means their nutritional intake, on an already poor diet, is cut by half.
Anger over rising food prices have already led to riots in Burkina Faso, Cameroon, Senegal and Morocco.