Tristram Stuart has 24 hours to produce a restaurant meal for 50 people—to plan a menu, gather food, then welcome guests to a venue in a city not his own. Complicating what sounds like a reality-show contest is a singular rule: Nearly all the ingredients must be sourced from farms and vendors intending to throw them out.

After racing back to New York City from a New Jersey farm where he gleaned 75 pounds of crookneck squash deemed by the farmers too crooked to sell, Stuart bolts from a car creeping through traffic and darts into a Greenwich Village bakery. Tall and blond, with a posh English accent, he launches into his ten-second spiel: “I run an organization that campaigns against food waste, and I’m pulling together a feast tomorrow made with food that won’t be sold or donated to charity. Do you have any bread that we could use?” The bakery doesn’t, but the clerk hands him two broken chocolate-chip cookies as consolation.

Stuart flings himself into the car. His next stop: the Union Square farmers market, where he spies a chef wrapping fish in squares of brioche dough, then trimming them into half circles. “Can I have your corners?” Stuart asks, with a meant-to-be-charming smile. The chef, uncharmed, declines. He’s going to make use of this dough himself. Undaunted, Stuart sails on through the market, delivering his pitch and eventually procuring discarded beet greens, wheatgrass, and apples.

View Images Near Apartadó, Colombia, activist Tristram Stuart examines bananas too short, long, or curved for the European market. Locals consume some rejected bananas, but growers in the region annually dump millions of tons of edible fruit.

Eighteen hours later scores of chefs, food-recovery experts, and activists talk shop over chef Celia Lam’s squash tempura, turnip and tofu dumplings, and spiralized zucchini noodles. Stuart himself had cooked very little, but he had, without a single formal meeting, ensorcelled a half dozen people to devise a menu, gather ingredients, and then prep, cook, serve, and clean up a meal for little more than the chance to be associated with one of the most compelling figures in the international fight against food waste.

Across cultures, food waste goes against the moral grain. After all, nearly 800 million people worldwide suffer from hunger. But according to the Food and Agriculture Organization of the United Nations, we squander enough food—globally, 2.9 trillion pounds a year—to feed every one of them more than twice over. Where’s all that food—about a third of the planet’s production—going? In developing nations much is lost postharvest for lack of adequate storage facilities, good roads, and refrigeration. In comparison, developed nations waste more food farther down the supply chain, when retailers order, serve, or display too much and when consumers ignore leftovers in the back of the fridge or toss perishables before they’ve expired.

Wasting food takes an environmental toll as well. Producing food that no one eats—whether sausages or snickerdoodles—also squanders the water, fertilizer, pesticides, seeds, fuel, and land needed to grow it. The quantities aren’t trivial. Globally a year’s production of uneaten food guzzles as much water as the entire annual flow of the Volga, Europe’s most voluminous river. Growing the 133 billion pounds of food that retailers and consumers discard in the United States annually slurps the equivalent of more than 70 times the amount of oil lost in the Gulf of Mexico’s Deepwater Horizon disaster, according to American Wasteland author Jonathan Bloom. These staggering numbers don’t even include the losses from farms, fishing vessels, and slaughterhouses. If food waste were a country, it would be the third largest producer of greenhouse gases in the world, after China and the U.S. On a planet of finite resources, with the expectation of at least two billion more residents by 2050, this profligacy, Stuart argues in his book Waste: Uncovering the Global Food Scandal, is obscene.

View Images In California’s Salinas Valley growers annually trash thousands of tons of fresh greens that lack sufficient shelf life for a cross-country journey.

View Images At a Paris feast chefs simmer cosmetically challenged veggies—gleaned or donated—into a curry for 6,100 anti-waste enthusiasts.

Others have been making similar arguments for years, but reducing food waste has become a matter of international urgency. Some U.S. schools, where children dump up to 40 percent of their lunches into the trash, are setting up sharing tables, letting students serve themselves portions they know they’ll eat, allotting more time for lunch, and scheduling it after recess—all proven methods of boosting consumption. Countless businesses, such as grocery stores, restaurants, and cafeterias, have stepped forward to combat waste by quantifying how much edible food isn’t consumed, optimizing their purchasing, shrinking portion sizes, and beefing up efforts to move excess to charities. Stuart himself has made a specialty of investigating conditions farther up the supply chain, where supermarket standards and ordering practices lead to massive, but mostly hidden, dumps of edible food.

Fifty miles north of Lima, Peru, in the farming town of Huaral, Stuart sips a glass of freshly squeezed satsuma juice with Luis Garibaldi, whose Fundo Maria Luisa is the largest grower of mandarins in the country. Pitched forward in his seat under a poolside pergola, Stuart asks: How much do you export? How much is rejected? For what reason? And what happens to those discards? Seventy percent of his crop, Garibaldi says, is exported to the European Union and North America. But 30 percent won’t be the right size, color, or sweetness, or it might have blemishes, scars, scratches, sunburn, fungus, or spiders. To local markets most of these rejects go, netting Garibaldi just one-third the price of the exports.

Stuart works through a ladder of queries that lead to a general thesis: Supermarkets’ cosmetic standards are crazily exacting—until supply shrinks, at which point they crumble like a chocolate lattice.

Lost En Route Every year some 2.9 trillion pounds of food—about a third of all that the world produces—never get consumed. Along the supply chain fruits and vegetables are lost or wasted at higher rates than other foods. Easily bruised and vulnerable to temperature swings en route from farm to table, they’re also usually the first to get tossed at home. Food loss Lost during production and processing Agriculture Postharvest Processing Food waste Discarded by retail markets and consumers Distribution Consumption Pick a region Or a type of food CHIQUI ESTEBAN, MANUEL CANALES, NG STAFF; TONY SCHICKSOURCE: FAO

“So grocers purchase this slightly imperfect fruit, and consumers still buy it?” Stuart asks.

“Yes,” Garibaldi says, nodding.

In the fragrant orchard, which lies in a valley under the parched crenellations of the Cordilleran foothills, Stuart plucks a mandarin unfit for any market but stops short of eating it. “I don’t mind maggots, actually, but that one was fermented,” he says, choosing instead a fruit with two tiny brown spots. Fundo Maria Luisa, it turns out, generates relatively little waste, thanks to its U.K. representative, who examines shipments and negotiates with any buyers poised to reject fruit for specious reasons. Often, Garibaldi says, a supermarket’s rejection of food for cosmetic reasons is merely a cover-up for its inaccurate forecasts or an unexpected drop in sales. Either way, the grower is expected to eat the loss.

View Images Thirty percent of the mandarin crop in Huaral, Peru, won’t meet exacting export standards. Most of the rejects will be eaten locally. Globally 46 percent of fruits and vegetables never make it from farm to fork.

We drive 200 miles south, past tall sand dunes and wind-eroded ridges. All is ocher and dust until we reach valleys suddenly verdant with irrigated farmland—a consequence of foreign investment, favorable trade agreements, cheap labor, a warm climate, and a once bountiful aquifer. In the Ica Region, Stuart interviews a farmer who annually abandons in his fields millions of stalks of asparagus too thin or too curved or with bud tips slightly too open to export. Next a producer tells him that he dumps more than a thousand tons of infinitesimally imperfect Minneola tangelos and a hundred tons of grapefruit a year into a sandpit behind his packhouse.

Grade standards—industry driven and voluntary—were devised long ago to provide growers and buyers with a common language for evaluating produce and mediating disputes. They also can help reduce food waste. If growers can sort their asparagus or tangelos into established grades, they stand a better chance of finding markets for their “seconds.” Supermarkets have always been free to set their own standards, of course, but in recent years upscale grocers have started running their produce departments like beauty pageants, responding to customers, they say, who expect only platonically ideal produce: apples round and shiny, asparagus straight and tightly budded.

“It’s all about quality and appearance,” says Rick Stein, vice president of fresh foods at the Food Marketing Institute. “And only the best appearance will capture share of the consumer’s wallet.” Some of the produce that doesn’t capture share will be donated to food banks or chopped up and used in a supermarket’s prepared meals or salad bar, but most of U.S. grocers’ excess food is neither donated nor recycled. Stuart applauds some U.S. and EU supermarkets’ recent campaigns to sell “ugly” produce at a discount, but he prefers a systemic fix. “It would be far better to simply relax the standards,” he says, surveying a sea of abandoned Peruvian citrus for which no secondary market—ugly or otherwise—exists.

View Images Gleaning for Good In the Picardy region of France a volunteer helps glean 1,100 pounds of potatoes too small to harvest mechanically. The potatoes will join carrots, eggplants, and other gleaned and donated vegetables at Paris’s Place de la République. There volunteers allied with Stuart’s group Feedback will chop this bounty into a meal for 6,100 diners. Feedback has helped organize more than 30 of these public feasts around the world to raise awareness of food waste and inspire local solutions.

For seven days Stuart traipses around farms and packhouses, runs through his questions, gathers data, and samples rejects. Between visits he folds himself like a fruit bat into the backseat of a crowded car and types. Tap, tap. He’s working out logistics for his next research trip, then accepting a drinks invitation from the general manager of the Food Bank of Peru. Tap, tap. An appointment with a food rescuer who just flew up from Santiago, Chile. Everywhere he goes, it seems, people want to tell Stuart an egregious story about food waste.

Sleep-deprived, unshaven, and sometimes hungover—what’s the point of being in a new country if you can’t sample what’s locally fermented?—Stuart remains focused. In fume-choked traffic he arranges to meet with a Peruvian congressman trying to overturn tax laws that incentivize dumping excess food over donating it. As we careen down a serpentine road, he taps out revisions to a proposed food-waste-reduction bill in the U.K. Parliament and a letter in support of expanding the authority of the U.K.’s Groceries Code Adjudicator. Next he floats to colleagues the idea of a Lima “disco soup”—a communal meal of rejected food, similar to the feast in New York City—to be held in four days for 50 to 100 people.

Reducing Waste: How You Can Help Developed countries are responsible for most of the food left uneaten on grocery-store shelves, on restaurant plates, and in home refrigerators. Here are some tips to reduce your waste footprint. AT A STORE AT A RESTAURANT Make careful decisions about what and how much you buy at the grocery store. • Shop at stores that offer misshapen food at a discount. • Purchase prepared meals at the deli or salad bar, which allows supermarkets to make use of imperfect produce. • Buy frozen foods, which suffer fewer losses from farm to shelf. • Shop often. Start with a large trip and then make smaller follow-ups to buy a few days’ worth of produce at a time. • Buy fresh food at local farmers markets. Americans spend about as much at restaurants as they do at grocery stores. • Skip the cafeteria tray. Diners who use trays waste 32 percent more than those who carry their plates in their hands. • Take home leftovers. • Share side dishes to keep portions under control. • Ask the waiter to hold extras such as bread and butter you don’t plan to eat. • Encourage restaurants and caterers to donate leftovers. AT HOME IN YOUR COMMUNITY Small changes in the kitchen can reduce the amount of food your household throws out. • Use FoodKeeper or other apps for food-expiration reminders. • Switch to smaller dishes to control portions. The standard plate is 36 percent larger than it was 50 years ago. • Eat leftovers on a regular night each week. • Give uneaten food a second chance. Freeze or can extras. Blend bruised fruit into smoothies. • Try not to waste water-intensive foods like meat. Businesses, schools, nonprofits, and governments can all find ways to dump less food. • Bring back home economics classes to teach cooking, canning, and storage basics. • Get your school to join the USDA Food Waste Challenge. • Ask your local government for a curbside food-scrap collection service like that provided in roughly 200 U.S. communities. • Share the bounty of your home garden with your community through ampleharvest.org. MANUEL CANALES, NGM STAFF Reducing Waste: How You Can Help Developed countries are responsible for most of the food left uneaten on grocery-store shelves, on restaurant plates, and in home refrigerators. Here are some tips to reduce your waste footprint. AT A STORE Make careful decisions about what and how much you buy at the grocery store. • Shop at stores that offer misshapen food at a discount. • Purchase prepared meals at the deli or salad bar, which allows supermarkets to make use of imperfect produce. • Buy frozen foods, which suffer fewer losses from farm to shelf. • Shop often. Start with a large trip and then make smaller follow-ups to buy a few days’ worth of produce at a time. • Buy fresh food at local farmers markets. AT A RESTAURANT Americans spend about as much at restaurants as they do at grocery stores. • Skip the cafeteria tray. Diners who use trays waste 32 percent more than those who carry their plates in their hands. • Take home leftovers. • Share side dishes to keep portions under control. • Ask the waiter to hold extras such as bread and butter you don’t plan to eat. • Encourage restaurants and caterers to donate leftovers. AT HOME Small changes in the kitchen can reduce the amount of food your household throws out. • Use FoodKeeper or other apps for food-expiration reminders. • Switch to smaller dishes to control portions. The standard plate is 36 percent larger than it was 50 years ago. • Eat leftovers on a regular night each week. • Give uneaten food a second chance. Freeze or can extras. Blend bruised fruit into smoothies. • Try not to waste water-intensive foods like meat. IN YOUR COMMUNITY Businesses, schools, nonprofits, and governments can all find ways to dump less food. • Bring back home economics classes to teach cooking, canning, and storage basics. • Get your school to join the USDA Food Waste Challenge. • Ask your local government for a curbside food-scrap collection service like that provided in roughly 200 U.S. communities. • Share the bounty of your home garden with your community through ampleharvest.org. MANUEL CANALES, NGM STAFF Reducing Waste: How You Can Help Developed countries are responsible for most of the food left uneaten on grocery-store shelves, on restaurant plates, and in home refrigerators. Here are some tips to reduce your waste footprint. AT A STORE AT A RESTAURANT AT HOME IN YOUR COMMUNITY Make careful decisions about what and how much you buy at the grocery store. • Shop at stores that offer misshapen food at a discount. • Purchase prepared meals at the deli or salad bar, which allows supermarkets to make use of imperfect produce. • Buy frozen foods, which suffer fewer losses from farm to shelf. • Shop often. Start with a large trip and then make smaller follow-ups to buy a few days’ worth of produce at a time. • Buy fresh food at local farmers markets. Americans spend about as much at restaurants as they do at grocery stores. • Skip the cafeteria tray. Diners who use trays waste 32 percent more than those who carry their plates in their hands. • Take home leftovers. • Share side dishes to keep portions under control. • Ask the waiter to hold extras such as bread and butter you don’t plan to eat. • Encourage restaurants and caterers to donate leftovers. Small changes in the kitchen can reduce the amount of food your household throws out. • Use FoodKeeper or other apps for food-expiration reminders. • Switch to smaller dishes to control portions. The standard plate is 36 percent larger than it was 50 years ago. • Eat leftovers on a regular night each week. • Give uneaten food a second chance. Freeze or can extras. Blend bruised fruit into smoothies. • Try not to waste water-intensive foods like meat. Businesses, schools, nonprofits, and governments can all find ways to dump less food. • Bring back home economics classes to teach cooking, canning, and storage basics. • Get your school to join the USDA Food Waste Challenge. • Ask your local government for a curbside food-scrap collection service like that provided in roughly 200 U.S. communities. • Share the bounty of your home garden with your community through ampleharvest.org. MANUEL CANALES, NGM STAFF

The possibility spurs a series of calls to his newest friends. “You are totally awesome,” he says, hyperenunciating. “Do you think we might be able to … It’s outrageous of me to ask but …” What’s the goal of the disco soup, besides rescuing food? Raising awareness and building community. This squishy stuff works. While gleaning, dicing, and dining, chefs from Lima to London have connected with charities hungry for their excess; California entrepreneurs have hatched schemes to rescue wonky-looking fruit from burial; civil society groups have fomented plans for a Kenyan food-rescue network; a Belgian brewer has been emboldened to convert stale bread into salable beer.

A disco soup in Lima seems harebrained, given that Stuart is five hours from the city, has a looming appointment at a Colombian banana plantation, controls neither a dining room nor a kitchen, and has no budget and no food. But history suggests he will probably succeed.

Stuart, now 38, was born in London, the last of three boys. He lived in the city part-time but at 14 took up full-time residence with his father in rural East Sussex, where the family kept a large house in Ashdown Forest, the model for Winnie-the-Pooh’s Hundred Acre Wood. Just across the valley lay what had been his grandparents’ estate, a sprawling property with enough farm staff during World War II to field a cricket team against the local village. Stuart’s father, Simon, had grown up there, and his stories about the farm’s bounty bewitched his youngest son.

Simon Stuart was a talented teacher of English and an outstanding naturalist. “We could never learn everything he knew,” Tristram recalls. “So my brothers and I split it up. One did birds, another did dragonflies, and I did mushrooms.” (Dining on a $22 pizza topped with “wild” mushrooms the night before his New York City feast, Stuart lights into the waiter. “Your menu is s---. I’m a forager. I know what wild mushrooms look like, and these are from a shop.”)

View Images Salvaging Scraps For more than 50 years RC Farms has been collecting Las Vegas kitchen waste and plate scrapings, like these zucchini sticks and fries from the coffee shop at Jerry’s Nugget Casino. Hauled a short distance to Bob and Janet Combs’s third-generation farm, the food scraps will be sterilized and fed to 2,500 pigs, replacing more than 800 tons of swine feed a year. Portions in U.S. restaurants have increased significantly in recent decades, contributing to obesity and food waste.

Living miles from the nearest town but psychologically close to his grandparents’ self-sufficient farm defined Stuart. His father tended a large vegetable garden, and Stuart added pigs and chickens to the mix. In exchange for manure, Simon gave Tristram his vegetable trimmings. “So I had eggs and meat, and I’d go out with my ferrets to catch rabbits and shoot deer,” Stuart says. The larder was almost complete. Stuart had begun selling pork and eggs to the parents of his schoolmates, but he quickly realized that buying animal feed would bankrupt him. He started a swill route: collecting misfit potatoes and stale cakes from local shops and his school kitchen. He bred his sow, Gudrun, and he learned how much edible food the community daily discarded.

Stuart’s environmental consciousness was expanding. At 12, he’d written a paper likening the burning of fossil fuels to smoking cigarettes—both were self-destructive and addictive. After spending part of a year on a French cattle farm, he entered the University of Cambridge, where he studied English literature and experienced a cruel uprooting from his agro-ecological heaven. The school food was produced “with no attention to sustainable criteria,” he says. In response he joined other campus activists who were dining on food they’d liberated from supermarket Dumpsters. He also drank cider pressed from strangers’ apples, shared the roasted brains, rolled spleens, and crisped ears of Gudrun’s many offspring, and—after learning they were tasty—slurped snails from friends’ gardens.

It’s not surprising to learn that Stuart once dabbled in theater. “I quite liked it,” he says, though it eventually threatened to “get in the way of the really important work of saving the planet.” He was sufficiently self-aware to realize that privileged students plucking unopened tubs of ricotta from rubbish bins had great rhetorical potential. At that time, he says, neither supermarkets nor government agencies had any overt policies on food waste. That was about to change.

View Images An employee at Las Vegas’s Aria Resort and Casino sorts the edible from the inedible. Feeding the scraps to nonruminant animals, such as pigs, recycles their nutrients and eliminates some of the methane that food would generate in a landfill.

By 2002 Stuart’s bin diving had attracted enough attention for him to help produce a food-waste documentary for a BBC politics show, and activists around the world were reaching out to him to partner on food rescues. (He was living then in London.) With enough data on where and precisely why food was lost throughout the food chain, he realized, he might actually be able to do something about it. Thus were sown the seeds of his book Waste, in which he investigated the causes and environmental toll of food waste around the globe.

Waste was critically acclaimed, but Stuart knew the data-heavy book wouldn’t be read by millions, and he desperately wanted millions to support his cause. “Hence, Feeding the 5,000,” he says, echoing Jesus’ instruction in John 6:12 to “gather the pieces that are left over. Let nothing be wasted.” Launched in 2009, Feeding the 5,000 would become Stuart’s flagship event—a free public feast made entirely of orphaned food. These gatherings have now been replicated in more than 30 cities. Thousands partake of the meals, reams of ink and pixels follow, and public outcry is amplified. Soon Stuart was giving speeches around the world and sharply criticizing the food industry’s most powerful actors, many of whom he put on the defensive with his polemics. Supermarkets, in turn, considered him “a pain in the ass,” he says. “And I was.”

From whence does Stuart’s formidable self-confidence spring? One hardly knows where to begin. Stuart is ambitious, aggressive, and narcissistic. But he’s also eloquent, amusing, and supremely knowledgeable on his central topic. “When he speaks, you want to join him,” says Dana Gunders, a food-waste specialist with the Natural Resources Defense Council who authored the Waste Free Kitchen Handbook. “He’s really good at not only kindling that passion in others but maintaining it, adding to the army of passionate people who want to do something about food waste.”

View Images At RC Farms, just ten or so miles from the Las Vegas Strip, hogs convert surplus potatoes from a local food processor into protein that may eventually find its way onto our plates.

Stuart takes every opportunity to eat low on the hog—the better to keep what’s uncoveted from rubbish bins and to model positive behavior. On his first morning in Peru he breakfasts on congealed chicken blood. “I’ve never had that before,” he says, happily. At lunch he exults in guinea pig. On day two he orders beef tripe; on day three, tongue and a great deal of pisco. Such is his macho carnivorism that when Stuart tells me he’s procured “fried balls” for a hasty airport lunch, I assume he’s talking about testicles. They turn out to be relatives of the potato knish.

The protein seems to fortify Stuart for farm and packhouse conversations that quickly grow weedy with numbers. Kilos, tons, containers, pallets, percentages rejected, recovered, left for dead. His stomach for such minutiae is large. “I want to be able to tell Europeans that their preference for a closed tip on their asparagus equals X million acres of land, X million gallons of water, and X million pounds of fertilizer wasted.” He takes a breath. “I need to make a headline, to tell people in a concise way that their choices matter.”

Indeed they do. With governments fretting over how to feed more than nine billion people by 2050, a dominant narrative calls for increasing global food production by 70 to 100 percent. But agriculture already represents one of the greatest threats to planetary health. It is responsible for 70 percent of the planet’s freshwater withdrawals, 80 percent of the world’s tropical and subtropical deforestation, and 30 to 35 percent of human-caused greenhouse gas emissions. As the population grows and emerging economies develop a taste for meat and dairy products, which require huge inputs of grain and other resources for relatively little caloric gain, this toll will worsen. But converting more wildlands to farm fields may not be necessary, some experts say. If we slash waste, change our diet to eat less meat and dairy, divert fewer food crops to biofuels, and boost yields on underperforming acres, we may be able to feed more than nine billion people a healthy diet without trashing more rain forests, plowing up more prairies, or wiping out more wetlands.

View Images Selling Surplus Staggered to learn that the U.S. wastes 30 to 40 percent of its food while one in seven people suffers from food insecurity, Doug Rauch, former president of Trader Joe’s, opened a nonprofit supermarket in Dorchester, Massachusetts. Called Daily Table, the supermarket sells discounted fruits and vegetables that are about to be discarded because they’re too close to peak freshness; it also sells inexpensive surplus goods and prepares healthy to-go meals. “Hunger and wasted food,” Rauch says, “are two problems that can have one solution.”

Stuart never loses sight of this big picture, but he knows that paradigm changes are incremental. And so he stands in the desert behind an Ica packinghouse, hammering away at Luis Torres, general manager of Shuman Produce Peru. Lacking a local market for what he cannot export, Torres annually dumps 3.5 million pounds of small or imperfectly spherical onions. But he’s reluctant to blame buyers for this loss.

“If I complain, the supermarket will find a new farmer,” he says, shrugging. “I am a practical person. I can do nothing to change the rules.”

Standing with his feet spread and arms crossed, Stuart replies, “I can.”

Three years ago Stuart spent a week running around the Kenyan countryside, hunting down ingredients for a formal dinner in Nairobi where the United Nations Environment Programme (UNEP) would highlight the problem of food waste. A hundred miles from the capital, he met a farmer forced by European cosmetic standards to reject 40 tons a week of green beans, broccoli, sugar snap peas, and runner beans—enough food to serve 250,000 people. Within a year Stuart and a camera crew returned to Kenya and discovered that farmers were grading out nearly half of their harvest in fields and packhouses, with green bean farmers losing even more product by trimming both the tips and the tails of each surviving bean. Supermarkets also routinely canceled orders at the last minute without compensating the farmers. After Feedback publicized images of the rejected beans and accused major supermarket chains of transferring their costs to relatively powerless growers, U.K. grocers were ready to talk. They eventually agreed to bear the cost of order cancellations and to expand the length of their packaging, which allowed green beans to be trimmed at only one end. Not only would less food and fewer resources be wasted, but farmers might also be able to plant fewer acres.

“Tristram identified a problem, and he did something about it,” says Clementine O’Connor, a consultant on sustainable food to the UNEP. “He’s been a lone voice defending farmers from unfair trading practices, identifying barriers, and catalyzing action, often in cases where supermarkets and governments were not aware of the problem.”

View Images Eating Ugly Imperfect, a start-up based in Emeryville, California, buys outré-looking produce from farmers and delivers it, at low cost, to more than a thousand San Francisco Bay Area subscribers. U.S. and European retail chains also have had success selling odd-looking fruits and vegetables at discount. “We’re redefining beauty, not taste,” says Ron Clark, an Imperfect founder.

Feedback’s 2015 report on Kenyan green beans was just one achievement in a watershed year. By the end of 2015 the UN and the U.S. had pledged to halve food waste by 2030. The exact mechanisms of this ambitious goal haven’t been spelled out. But already countries and companies are devising and adopting standardized metrics to quantify waste. If the target is met, enough food could be saved to feed at least one billion people.

On an overcast Thursday afternoon in September, Stuart strides through a muddy field in northern France. He plunges his hands into a mound of soil and extracts several thin-skinned potatoes, which, being the size of thimbles and thumbs, had slipped through the mechanical harvester’s grasp. For the next hour and a half he and a team of gleaners comb through the soil. The goal is to gather 1,100 pounds of spuds for Sunday’s Feeding the 5,000 event, to be held in Paris’s locus of civic activism, the stately Place de la République. The next day Stuart and another team of volunteers from partner organizations wash their enormous haul in a ramshackle squat in the 12th arrondissement. Standing shirtless in a cluttered room redolent of sweat and pot, with music blasting, Stuart scolds a woman for wasting time by scrubbing the potatoes twice. Feeling bullied, she blurts a two-word vulgarism. Stuart crows, “That’s what everyone says to me!”

On Saturday it’s time to chop. Gathering at rows of plastic tables in the square, hundreds of volunteers come and go over a period of four hours, dicing roughly 3,900 pounds of potatoes, eggplants, carrots, and red peppers—some gleaned from farms, some donated by the Rungis wholesale market. Mostly veterans of mass production, the helpers shuttle produce from crates to giant plastic bowls and then to blue plastic bags. At 5 a.m. on Sunday the chef, Peter O’Grady, a Hare Krishna who runs a charity kitchen in London, tips those bags into chest-high metal tanks atop gas burners.

As midday approaches, the park grows crowded. Musicians perform onstage, and two-legged carrots and eggplants parade and chant, “No more vegetable waste!” Stuart is absent, his presence superfluous. As 6,100 diners begin to queue up, the servers don gloves, hats, and aprons. At noon Stuart materializes. He mounts the stage and grabs the mike. He thanks everyone who made the banquet possible, calls food waste a scandal, briefly links agriculture to climate change, then withdraws from the stage. But not before shouting, “Bon appétit.”