On Thursday night, that something looked like this: In a fraying section of downtown Rio, a pack of the world’s most venerated chefs were rushing around a slapdash kitchen amid a crush of volunteers as they improvised a dinner for 70 homeless people.

All of the ingredients, most of which might have otherwise been thrown away, had been donated, as had the labor of the chefs and orange-aproned servers, some of whom had traveled to Rio from California, Germany and Japan.

The creators of this place, Refettorio Gastromotiva — refettorio means dining hall in Italian — hope it will change the way Brazilians, and the world, think about hunger, food waste and the nourishing of human dignity.

“This is not just a charity; it’s not just about feeding people,” said Mr. Bottura, pausing to pick up trash from the forlorn playground outside his new venture. “This is about social inclusion, teaching people about food waste and giving hope to people who have lost all hope.”

In the days since it began operating on Wednesday out of a hastily erected translucent box in the downtrodden neighborhood of Lapa, Refettorio Gastromotiva has become something of a sensation: a feel-good counterpoint to the commercialization of the Games, and to the gluttony that unfolds each night in the pop-up pavilions that many countries have set up throughout the city.