Some 17% of food is wasted at the consumer level, even in non-affluent countries, according to a new United Nations report.

The report was co-authored jointly by the United Nations Environment Program and WRAP, a nonprofit organization that works with governments to fight food waste. It said waste occurs at retail stores, restaurants and homes.

"For a long time, it was assumed that food waste in the home was a significant problem only in developed countries," Marcus Gover, CEO of WRAP, told Reuters. "With the publication of the Food Waste Index report, we see that things are not so clear cut."

The waste by consumers is part of a general pattern that ends up wasting one-third of the world’s food output every year, according to an estimate by the UN’s Food and Agriculture Organization. Consequences include pollution, not just from discarded food and the greenhouse gases it often produces, but from the energy required to transport and process it, deforestation to make its packaging, and other sources.