Hunger is costing the world's poorest nations 450 billion US dollars (£290 billion) a year, according to a new report.
The figure is more than 10 times the estimated amount needed to meet the United Nations Millennium Development Goal (MDG) of halving global hunger by 2015, said the report by charity ActionAid.
The UN will gather in New York next week to assess progress towards the eight goals set in 2000, with Deputy Prime Minister Nick Clegg representing the UK.
But with just five years to go to the MDG deadline, the report ,entitled Who's Really Fighting Hunger?, warned that many countries are going backwards on the crucial hunger pledge, with more people under-nourished than a decade ago.
If the massive gains made in China are excluded, global hunger rose to the same level in 2009 as it was at in 1990, with 500 million more people chronically malnourished than if the UN goal had been met, said ActionAid.
The charity warned that hunger has a cost not only in premature deaths, but also in lost economic potential. Developing economies are losing out to the tune of 450 billion dollars a year because their people are too hungry to work or because hunger in childhood has left irreversible damage to their mental and physical capacities.
ActionAid said "political will" was the key to hitting the 2015 target, pointing to success stories like Brazil, which has halved the number of underweight children in less than a decade, and Malawi, where numbers living on food handouts have been cut from 4.5 million to 150,000 in just five years.
The charity urged the rich world to make good on 22 billion dollars (£14 billion) to fight hunger pledged at last year's G8 summit in Italy. And it called on Mr Clegg and the new coalition Government to "show leadership" by prioritising hunger as a key development issue.
Britain ranks seventh in the ActionAid league table of 23 donor countries - and fourth for aid to agriculture. But the charity warned the coalition must not allow the UK to "fade as a leading light in global development".
ActionAid head of policy Meredith Alexander said: "On the eve of the most important development summit for five years, a billion people will be going to bed hungry. Despite promises to the contrary, one-sixth of humanity doesn't get enough to eat. But we grow enough food to feed every man, woman and child on the planet. The real cause of hunger isn't lack of food, it is lack of political will."