TULSA, Okla. — On a recent Friday afternoon, in the parking lot of a Dollar General in the North Tulsa neighborhood of Greenwood, Jessica Faulk loaded a frozen pizza and other snacks for her grandkids into her car. This was her first trip to the store, which sits near an elementary school and a housing complex for seniors. Though she lives nearby, she’d been avoiding the retailer for more than a year out of principle, and usually shops at a Walmart in the suburb of Sand Springs.

It’s not necessarily this dollar store that’s the problem. It’s the sheer number of them. The City Council district where Ms. Faulk lives already has nine dollar stores and not a single high-quality grocer. This one actually does carry a small amount of produce, but it’s not nearly enough. “All you see is these types of stores over here,” says Faulk. “It’s a Band-Aid or a pacifier for the lack of an actual grocery store.”

Here and in communities across the country, the dollar store has supplanted the grocery store as the place where many Americans buy their food. Dollar General and its rival Family Dollar (which was acquired by Dollar Tree in 2015) have scattered 24,000 stores across urban and rural landscapes, more than 8,000 of them opened in the last decade alone. The chains draw an ever-growing percentage of their sales from food, much of it high in calories and low in nutrients, like the Doritos in the central aisle at the store on Pine Street. Stores that were once conveniences are now the only places to buy food in some communities.

Cities often accept this fate. In fact, they encourage it. Since 2001, Dollar General and Dollar Tree have received more than $130 million in tax breaks and other financial incentives around the country, according to Good Jobs First, an organization that tracks government subsidies.