Imagine eating a meal made entirely of food that was originally destined for the trash can. Now bring 4,999 of your closest friends with you. That is the idea behind Feeding the 5000, an event spearheaded by Tristram Stuart, an author, campaigner, and National Geographic Emerging Explorer who is focused on reducing food waste.

Food waste is a big problem. “At least a third of the world’s current food supply is being wasted,” Stuart told National Geographic. “We need to make everyone believe that food is far too valuable to waste.” The United Nations (UN) agrees. One of the United Nation's goals is to ensure that people worldwide have access to sufficient quantities of nutritious food by the year 2030. This is a lofty goal but an important one; roughly 815 million people already go hungry today, according to the UN.

Stuart, who was born in the United Kingdom (UK) in 1977, has been campaigning about food waste for over twenty years. The National Geographic Explorer has helped organize Feeding the 5000 events around the world in cities such as New York City, New York; Milan, Italy; and Paris, France. These events are spearheaded by Feedback, the charity Tristram founded, which oversees a network of people who harvest fruits and vegetables that would otherwise go to waste. Feedback also campaigns for other causes, such as allowing pigs to be fed food waste rather than soy and grains, which are often grown on deforested land.

In addition to his work with Feeding the 5000 and Feedback, Stuart has written two books on food and food waste: Waste: Uncovering the Global Food Scandal and The Bloodless Revolution: A Cultural History of Vegetarianism from 1600 to Modern Times.

In 2011, Stuart was awarded The Sophie Prize, an international environmental award. The prize committee recognized that “Stuart shows how simple changes can be introduced by consumers, politicians, and businesses to dramatically reduce waste.”

Changing how the world’s food is distributed and consumed is Stuart’s passion. There have been positive changes already—for example food redistribution has doubled in the UK—but there is still plenty to do. “We will and we can change the way the whole food system is being run,” Stuart told National Geographic. “It’s our responsibility to do that.”