The move comes one day after the president of the World Bank, Robert Zoellick, called on the international community to act urgently in helping needy people and "put our money where our mouth is." Haiti, Egypt and the Philippines are among the countries facing civil unrest because of food prices and shortages.
Bush directed Agriculture Secretary Ed Schafer to draw down an estimated $200 million from a food reserve known as the Bill Emerson Humanitarian Trust.
White House press secretary Dana Perino said the move will help address the impact of rising commodity prices on U.S. emergency food aid programs, and help meet the unanticipated food needs of countries in Africa and elsewhere.
Bush discussed the hunger problem at length with his Cabinet at the White House on Monday.
Perino said Bush was deeply concerned about the mounting crisis, and that he believes developed countries have a responsibility to help those in need.
Beyond short-term aid, Perino said administration officials are debating solutions with lasting impact. "Over the long run, the source problems will need to be identified, the source of where the food is, so that there is a long-term plan in place that helps take care of the world's poor and hungry," she said.
Perino noted the United States already is the largest provider of food aid in the world. The United States delivered more than $2.1 billion of food aid to 78 developing countries in 2007, she said.
Earlier Monday, United Nations Secretary-General Ban Ki-moon warned that a rapidly escalating global food crisis has reached emergency proportions and threatens to wipe out seven years of progress in the fight against poverty.
He called for short-term emergency measures in many regions to meet urgent food needs and avoid starvation and longer-term efforts to significantly increase production of food grains.
The "international community will also need to take urgent and concerted action in order to avoid the larger political and security implications of this growing crisis," Ban told international finance and trade officials who came to a U.N. meeting following weekend talks in Washington.
The secretary-general echoed Zoellick's appeal to governments on Sunday to quickly provide the U.N. World Food Program with $500 million in emergency aid that it needs by May 1.
Zoellick said the international community has "to put our money where our mouth is" to deal with rapidly rising food prices that have caused hunger and deadly violence in several countries.
Ban said the recent steep rise in food prices "has already raised the cost of WFP's needs to maintain its current operations from $500 million to $755 million."
WFP, the world's largest humanitarian agency, issued an "extraordinary emergency appeal" to donor countries for $500 million last month, saying the money was needed by May 1 to avoid cutting rations to some of the world's most impoverished regions. The Rome-based agency said its funding gap was growing weekly.
"The rapidly escalating crisis of food availability around the world has reached emergency proportions," Ban said.
"The World Bank has estimated that the doubling of food prices over the last three years could push 100 million people in low income countries deeper into poverty," he said.
Ban echoed Zoellick in warning that that the food crisis "could mean seven lost years in the fight against worldwide poverty."
The United Nations is at a midpoint in its campaign to reduce global poverty and improve living standards of the world's bottom billion. The Millennium Development Goals, adopted at a U.N. summit in 2000, include cutting extreme poverty by half by 2015.
The World Food Program blames soaring food prices on a convergence of rising energy costs, natural disasters linked to climate change, and competition for grain used to make bio-fuels like ethanol.
Program spokesperson Benita Luescher told CBS News correspondent Michelle Miller, "What we're seeing is a perfect storm."
On Friday, the Group of 24 Developing Countries urged advanced nations to step up financial aid to help them deal with the severe impact of higher food and energy prices and the turmoil in global financial markets.
The G-24 said that coordinated international action is needed to prevent the emergence of a larger crisis, and agreed the International Monetary Fund has an important role in responding to the current crisis. They also urged the IMF's sister institution, the World Bank, to increase advice and financial support.