Greek volunteers help prepare food for an event that highlights food waste around the world. Feedback

On Sunday, thousands of Greeks filled Athens’ central square. They were there not to protest -- but simply to eat. Specifically, they feasted on tons of briam, a vegetable dish that includes eggplant, zucchini, carrots and potatoes. A dessert of fruit salad was served as well, according to the Associated Press.

The free food was served by a global nonprofit called Feedback, whose mission is “to shine a light on the global food waste scandal” by serving fruits and vegetables that were rejected by stores. The group notes that, according to the United Nations Food and Agriculture Organization, about 1.3 billion tons of fruits and vegetables are wasted globally each year.

The yearly event, Feeding the 5,000, began in London’s Trafalgar Square in 2009. Since then, Feedback events have expanded to Paris, Dublin, Sydney, Amsterdam, Brussels and Manchester, England.

Tristram Stuart, the founder of the event, is a global food activist who wants the developed world to stop wasting so much food. He says that grocery stores in Western countries refuse to buy misshapen fruits and vegetables, and much if not all of those discarded items go to waste, even though they are edible and could be used to feed the hungry.

"Everywhere I looked, we were hemorrhaging food," he told National Geographic recently. "So I began confronting businesses about the waste and exposing it to the public."

Some food retailers are beginning to take note. In 2014, French supermarket Intermarche started a campaign to convert their “hideous fruits and veggies” into their best-sellers. “In TV commercials and print ads, the supermarket promoted absurd-looking produce like 'the grotesque apple,' 'the failed lemon,' 'the disfigured eggplant,' 'the ugly carrot' and the 'unfortunate clementine.'” NPR noted.

Sunday’s event in Greece was a lead-up to World Food Day Oct. 16, a global event that highlights food waste and hunger around the world.