Oakland is a city that's rapidly gentrifying, shedding much of its African-American population along the way. The California city, which was 47 percent black in 1980, is now divided roughly into a quarter each of black, white, Asian and Hispanic residents.

The sense of the city's changing identity has ended up helping Adrian Henderson's business. He's co-owner of Kingston 11 Cuisine, a Caribbean restaurant in a neighborhood that's changed so much lately that it goes by the dual name of Koreatown Northgate.

"Here in Oakland, folks are seeing black folks being pushed out," Henderson says. "We're a community-based restaurant, so people of color are supporting our business. Any black-owned business or restaurant is being over-supported now, which is great, right?"

To help spread the word about which restaurants are in fact owned by African-Americans, Henderson participates in Bay Area Black Restaurant Week. Over the past couple of years, such promotions have spread to essentially every major city with a substantial African-American population, including Houston, Detroit, Charlotte, Atlanta and New Orleans, along with smaller cities such as Richmond, Va., and Madison, Wis.

"Some of the restaurants that participate in black restaurant week want to remind African-American consumers that are conscientious with their dollars that they're there," says Marcia Chatelain, a Georgetown University historian who is working on a book about race and fast food.

During the promotions, diners can often receive multi-course meals at a discount. In some cities, however, it's simply a way of drawing attention to what's on offer all the time at black-owned restaurants, a pure exercise in branding and promotion. Chicago's version is going on this week. Baltimore's Black Restaurant Challenge is continuing throughout most of February. Other cities will follow course throughout the spring.

The idea seems to have spread around the country largely through social media, with local events sponsored variously by public relations consultants, a wine distributor, a radio station and the restaurants themselves.

Lauran Smith, the organizer of Chicago Black Restaurant Week, works as a public school guidance counselor. "For me personally, it came from the fact that I really did not feel like I was celebrating my history enough, and food is something I like," she says. "I created black restaurant week for Chicago to celebrate the fact that we have a lot of delicious businesses in our community."

Spreading the word has worked. In 2016, eight restaurants participated in Memphis Black Restaurant Week, attracting a total of 3,135 customers. Last year, the number of restaurants grew to 14, which collectively saw more than 6,200 patrons walk in the door over the course of the week.

It wasn't rocket science, says Cynthia Daniels, a social media manager who came up with the idea in Memphis. The city already held celebrations for nearly every other type of food — Italian, Mexican, barbecue. HM Dessert Lounge, the black-owned restaurant she was working with, didn't have a marketing budget. By banding together with others, the event was able to draw a considerable amount of publicity, which has also been the case in other cities.

"When black restaurant week started, we were new, so it gave us a lot of exposure," says Terrence Callicutt, an owner of Scoops Parlor, a Memphis ice cream shop that also serves sandwiches and crepes.

The type of restaurants that are included in various cities range from takeout joints that serve fried fish and chicken to high-end establishments such as the 40/40 Club in Manhattan, a lounge co-owned by hip hop mogul Jay Z.

Overall, African-Americans lag when it comes to running restaurants. Blacks make up 13 percent of the population, but only 8 percent of restaurant owners and the same share of restaurant managers, according to the National Restaurant Association.

There are African-Americans who are celebrity chefs, such as Carla Hall and Pat Neely. In general, however, blacks often struggle to come up with the capital necessary to open and run restaurants, in part due to the legacy of lack of wealth formation among African-Americans and ongoing discrimination. "Most black restaurant owners, they take their life savings, open the restaurants and hope for the best," Daniels says.

Black ownership of restaurants, along with other types of businesses, was often more robust during the Jim Crow era of segregation, at least in some cities. Black-owned businesses served black customers that white owners could not or would not. "There have been black-owned restaurants as long as there have been racially segregated neighborhoods," says Sharon Zukin, a sociologist at Brooklyn College.