At Rosa's Fresh Pizzeria in Philadelphia, customers buy a dollar slice, then opt to top it off with another dollar to feed a homeless person.

In Denver, SAME Cafe has no prices on its menu. Instead, diners are asked to either leave a donation or help bus tables or wash dishes in exchange for their meal. A similar philosophy governs JBJ Soul Kitchen in Red Bank, N.J., where a three-course meal might include gazpacho, Cuban pulled pork and dessert.

And at Crescent City Cafe in New Orleans, volunteers serve lemon poppyseed pancakes and sausage and mushroom casseroles to those in need twice a month, supported in part by brunch fundraisers featuring the same gourmet meals and asking diners to pay it forward.

The concept is simple: feed someone in need at the same time you feed yourself. In the last few years, charitable dining has been quietly building momentum around the world in the form of pay-what-you-want cafes and buy-one give-one models often launched by Millennial entrepreneurs. In Canada, a broader nonprofit program called Mealshare has built a network of 200 restaurants that donate a meal to charity every time a qualifying meal is ordered from their menus.

“It's a way to give back to the community in a meaningful way that fits their business," says Mealshare co-founder Jeremy Bryant, 26.

Spearheaded by TOMs Shoes, which began in 2006 with the promise to donate a pair of shoes for every pair purchased, the buy-one give-one model has been embraced by companies selling everything from eyewear and soaps to granola bars. Some critics, however, question the model's ability to offer long-term solutions to homelessness and poverty.

Mason Rosas Pizza
Rosa's Pizza owner Mason Wartman

“It pleases you more than it helps anything," Andreas Widmer, director of entrepreneurship programs at Catholic University, noted in Knowledge, an online business analysis journal run by the Wharton School of the University of Pennsylvania. "To give anything is always a bad idea when you're trying to fight poverty."

But supporters defend it as an effective, if short-term, way to make an impact and bring disparate groups together through the sharing of meals.

“We would love nothing more than for a long-term solution to hunger and poverty to emerge," says Arthur Kraatz, operations director of Crescent City Cafe. “In the meantime, however, there are people on our streets that struggle to eat on a daily basis." Kraatz aspires to turn Crescent City Cafe into a full-time operation "that serves the same delicious, creative meals to those with means and those without."

Mealshare, Bryant points out, partners with charities that not only provide meals but also offer programs like counseling and access to education and affordable housing. "Each of our partner charities operates differently, but the consistent thing about them is they serve great food to people in need and are solution-based and focused on ending the cycle of hunger/poverty," he explains.

For his part, Mason Wartman admits he wasn't thinking about feeding the hungry when he left his Wall Street desk job to open Rosa's Fresh Pizzeria in 2013. “I had plateaued and wanted to own my own business," he said. "I liked the dollar-slice business model I saw in New York." 

Wartman added the buy-one give-one model last year after a customer came in and asked him if anyone ever came up short.

Rosas Pizza

“He told me about these cafes in Italy that let customers pre-purchase cups of coffee for the less fortunate," said the 27-year-old, who also sells $8 whole pies. The man left an extra dollar, so Wartman took it and slapped a Post-It note on the wall by the register to be redeemed by the next homeless person to walk in.

Since then, Rosa's has given out more than 20,000 pre-purchased slices, and its walls are lined with thousands of multi-colored Post-It notes from grateful customers.

In April, the Coca-Cola Company offered to donate a bottle of Dasani water for every pre-purchased slice. “That's been huge," Wartman said. “It fulfills another need."

Rosas Pizza

Paying it forward with pizza is also at the central core of Random Acts of Pizza, a spin-off web site of the open-source online community Reddit. It allows Reddit members to post requests for pizza, and other members may opt to fulfill them. A 2014 Stanford University study found that requests from people with compelling personal stories related to family, money or jobs were more successful than those who simply seemed to be craving a pizza.

While those involved say the rewards are significant, challenges remain in the charitable dining arena. Last summer, Rosa's Pizzeria nearly ran out of pre-purchased slices to meet demand as Philadelphia's homeless population swelled due to the warm weather, Wartman said. And Bryant recalls the struggle he and his two partners had initially persuading restaurant owners to sign on to Mealshare.

"We called, emailed and visited over 50 restaurants to get them to try Mealshare out — and we got a lot of no's," he recalled. "It was a new idea, and they did not know if it would be meaningful."

In the end, everyone agrees that the model succeeds in fulfilling one of its core missions: reminding those who are struggling that they matter.

"Mostly, we just try to serve food to our guests that we would enjoy eating ourselves," says Kraatz of Crescent City Cafe. "Inviting them into a friendly place to sit down and enjoy a warm meal among friends not only solves their hunger problem in the short term, but it reminds them that people care about them."