Global food crisis is threatening to roll back even the slow social progress the world's 50 Least Developed Countries (LDCs) have achieved so far, the UN Conferenceon Trade and Development (UNCTAD) said on Thursday.

Since most people in LDCs are poor and a large share of their income is spent on food, they have been hit hard by rising prices,the UN agency said in its 2008 Least Developed Countries Report.

Poor people can now afford fewer other products and increasingly buy lower-quality food, thus raising the danger of malnutrition. That, in turn, will have adverse consequences for health and education, the report said.

According to the report, the prices of staples such as maize, wheat and rice have doubled in some LDCs since 2007.

This situation even resulted in food riots in eight LDCs between 2007 and the first half of 2008. The eight countries are Burkina Faso, Guinea, Haiti, Mauritania, Mozambique, Senegal, Somalia and Yemen.

The report said that despite their high economic growth rate inrecent years, the total number of poor people is still rising in LDCs.

Overall economic growth rates of 7 percent and more in the LDCsin 2005-2006 should have provided an opportunity for substanital improvements in living conditions, the report said.

But three fourths of those living in these nations continue to survive on less than two U.S. dollars per day. Most people cannot meet basic needs for food, water, shelter, health or education.