US chef Dan Barber takes part in the presentation of the Basque Culinary Center, on July 26, 2010, in the northern Spanish Basque city of San Sebastian

World leaders accustomed to fine dining had a surprise on their plates Sunday at the United Nations—trash.

Chefs cooked up a lunch made entirely of food that would have ended up in garbage bins, hoping to highlight the extraordinary waste in modern diets and its role in worsening climate change.

On the menu for the lunch at the UN headquarters was a vegetable burger made of pulp left over from juicing, which typically wastes most of the produce.

The burger came with fries created from starchy corn that would typically go to animal feed—which along with biofuels is the end product of the overwhelming majority of the 90 million acres (36 million hectares) of corn grown in the United States.

"It's the prototypical American meal but turned on its head. Instead of the beef, we're going to eat the corn that feeds the beef," said Dan Barber, a prominent New York chef who co-owns the Blue Hill restaurant.

"The challenge is to create something truly delicious out of what we would otherwise throw away," he told AFP.

Barber crafted the menu with Sam Kass, the former White House chef who drove the anti-obesity "Let's Move" campaign of first lady Michelle Obama.

Kass thought of the waste-lunch concept as he learned about year-end UN climate negotiations in Paris, which aim to reach a far-reaching global agreement to tackle the planet's worsening climate change.

"Everybody, unanimously, described it as the most important negotiation of our lifetime," he said.

But food waste "was not something that was being discussed at that point, except in small environmental circles," he said.

US First Lady Michelle Obama (C) receives some planting advice from White House Assistant Chef Sam Kass (L) while planting vegetables with children at Bancroft Elementary School, May 29, 2009, in Washington, DC

Vast contributor to climate change

Major world leaders took part in Sunday's lunch that was led by French President Francois Hollande and Peruvian President Ollanta Humala with an aim of building momentum for the Paris talks.

The United Nations welcomed the two chefs for the lunch, even though the world body rarely brings in outside cooks, especially during the ultra-high-security General Assembly.

According to UN figures, 28 percent of agricultural lands around the world go to produce food that is lost or wasted.

The loss each year is the equivalent of 3.3 billion tonnes of carbon responsible for climate change—which would make food waste, if it were a nation, the biggest emitter after China and the United States.

"It's just unthinkable, the inefficiency in our system, particularly when you look at something of this magnitude," Kass said.

'Delicious' social change

Barber earlier this year ran a pop-up restaurant in New York sourced from food scraps and is the author of the book "The Third Plate" that has championed a global approach to his farm-to-table philosophy.

Russian Foreign Minister Sergey Lavrov speaks to the United Nations Sustainable Development Summit at the United Nations General Assembly on September 27, 2015

He said that the elimination of food waste was in fact an ancient rather than modern idea, as historically cooks would use everything edible at their disposal.

"The idea of doing a 'waste dinner' would not have existed in the 1700s," he said.

"The Westernized conception of a plate of food is enormously wasteful because we've been able to afford waste," he said.

Food waste rates are even higher in the United States, which is blessed with vast agricultural resources.

White House Chef Sam Kass (C) serves food to members of the press, prepared with help from Zach Strief (R), a member of the 2010 Super Bowl Champion New Orleans Saints, at the Briefing Room at the White House in Washington, DC, August 9, 2010

Barber expressed hope that events such as the lunch could gradually change food culture.

"The long-term goal of this would be not to (be able to) create a waste meal," he said.

"You don't do that by lecturing—you do it by hedonism, by making these world leaders have a delicious meal that will make them think about spreading that message."

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© 2015 AFP