A study by the Swedish Institute for Food and Biotechnology, commissioned by the FAO for an international congress in Germany, said the amount of food lost or wasted every year is more than half the world's cereals crop of 2.53 billion tons last year.
Fruits, vegetables, roots and tubers account for the highest wastage rates of any food, the study said.
Consumers in rich countries waste almost about 244 million tons of food every year, which compares with the entire net food production of sub-Saharan Africa of 253 million tons.
Food losses -- defined as occurring at the production, harvest or processing phases -- are a problem in developing countries due to their poor infrastructure, low levels of technology and low investment in the food production systems, the study said.
Food waste is more a problem in industrialized countries, most often caused by both retailers and consumers trashing perfectly edible food items.
The study said total per capita food production for human consumption is about 900 kilos (1,984 pounds) a year in rich countries, almost twice that produced in the poorest regions.
Food losses and waste also cause waste of valuable resources including water, land, energy, labor and capital and contribute to greenhouse gas emissions and global warming.
The study said the food supply chain can be strengthened by assisting small farmers to link up directly with buyers. It said private and public sectors should also invest more in infrastructure, transportation and in processing and packaging.