About one third of all food produced for human consumption goes to waste, according to a study commissioned by the United Nations food agency.
That amounts to more than one billion tonnes of waste around the world every year.
The study recommends that developing countries should improve production and distribution, so as to stop losing so much food.
It also says industrialised countries must stop throwing so much away.
Loss versus waste
The UN study, by the Swedish Institute for Food and Biotechnology, was aimed at an international trade fair for the food packaging industry, to be held in Germany later this month.
Among the key findings are that consumers in rich countries waste almost as much food, 222 million tonnes, as the entire net food production of sub-Saharan Africa.
Unsurprisingly, the researchers found that fruit and vegetables - including roots and tubers - go to waste more than other types of food.
But the report, entitled Global Food Losses and Food Waste, has a different analysis of the problem for different types of economy.
Commissioned by the UN Food and Agriculture Organisation (FAO), it distinguishes between food loss and food waste.
Losses happen during the production, processing and distribution of food. They affect developing countries worst. The answer is to improve technology and infrastructure, the study says.
Food waste is the big issue in industrialised countries. It is mainly due to retailers and consumers throwing perfectly edible food into the bin.
Waste amounts to around 100kg (more than 200lb) per consumer in Europe and North America every year.
Consumers in sub-Saharan Africa and most of Asia each throw away just 6-11kg.
At retail level, large quantities of fresh food is wasted because of the way it looks. The Swedish researchers reviewed surveys showing that consumers were willing to buy produce that looks imperfect, as long as it is safe and tastes good.
Customers have the power to influence quality standards and should do so, the report says.
And it criticises "buy one, get one free" promotions for their tendency to lead to waste.
Food loss and waste are also a major squandering of resources - water, land, energy and labour - and contribute to greenhouse gas emissions.