UN Secretary General Ban Ki-moon has said he is deeply concerned about the sharp rise in global food prices.
Mr Ban said the trend would hinder progress towards the millennium development goals (MDGs), which aim to halve extreme poverty by 2015.
The UN World Food Program (WFP) and other agencies may be forced to ration food aid, he said in a BBC interview.
He said shortages might be eased by a “green revolution” to transform farming methods in Africa.
Global food prices have risen by 40% in nine months and food reserves are at their lowest for 30 years.
The WFP is facing a $500m (£248m) shortfall in its attempts to feed 73 million people this year.