Stockholm, Aug 21 - The United States and some other developed states throw away nearly a third of their food each year, according to a report that said on Thursday the world was producing more than enough to feed its population.
The report, produced by the United Nations Food and Agriculture Organisation (FAO), the International Water Management Institute (IWMI) and the Stockholm International Water Institute, called for a 50 percent reduction in the amount of food wasted after production by 2025.
Since huge amounts of water are required to produce crops and other foodstuffs, cutting waste would boost water supplies for agriculture and household use.
"More than enough food is produced to feed a healthy global population," said the report, released during an annual week-long conference on global water issues in Stockholm.
The authors said that in the United States, up to 30 percent of food, worth some $48.3 billion, is thrown away each year.
"That's like leaving the tap running and pouring 40 trillion litres of water into the garbage can -- enough water to meet the household needs of 500 million people," the report said.
The report did not provide rankings in terms of waste but said similar levels were reported in Europe.
It cited a study showing one third of food in Britain was thrown away, with a high percentage untouched and in its original packaging. In Sweden, families with small children throw away about 25 percent of the food they have bought and brought home, the report said.
As much as half the water used to produce food globally may be wasted, said Dr Charlotte de Fraiture, a researcher at IWMI.
Further pressure on water and food production is coming from demand for biofuels, from water-intensive agriculture such as beef production and from population growth.
These trends will spark crises in many places, particularly in sub-Saharan Africa and South Asia, the report said.
"Unless we change our practices, water will be a key constraint to food production in the future," said Pasquale Steduto of the United Nations FAO.