Dollar stores are now the fastest-growing food retailers in the contiguous United States—and have doubled their share in rural areas, according to a new study.

Households with more purchases at dollar stores also tend to be lower-income and headed by people of color. The study in the American Journal of Public Health could have meaningful implications for nutrition policy.

Food and beverages stocked by dollar stores are typically lower in nutrients and higher in calories, while only a small percentage of such shops carry fresh produce and meats. Their growing footprint, especially in the remote South, is also important: These regions already have higher baseline levels of obesity and food insecurity.

In general, as people’s income goes up, they spend less of their budget at dollar stores, the researchers found. But they also found that in rural and low-income areas, people spend on average more than 5% of their food budget at dollar stores. In particular, rural non-Hispanic Black households spend 11.6% of their food budgets in dollar stores. Households in the rural South also spend in large numbers.

“The South is a hot spot,” says Cash, a food economist. “The dollar-store business model originated in the South. They have more distribution centers there, and consumers there have supported this growth.”

It’s a notable evolution: Dollar stores once focused primarily on personal care and craft items. Now, they’re expanding to offer prepackaged, shelf-stable food items. These items might be convenient, but they often have suboptimal nutritional value.

Read the full article about dollar stores as food sources at Futurity.