Food deserts exist because of a layered set of forces: decades of racial and economic disinvestment in certain neighborhoods, grocery industry economics that favor wealthier suburbs, transportation gaps, zoning rules that block alternatives, and in rural areas, sheer distance combined with the decline of independent grocers. About 18.8 million Americans, roughly 6% of the population, live in areas the USDA classifies as low-income and low-access to healthy food.
What Counts as a Food Desert
The USDA defines a food desert (officially called a “low-income, low-access” area) using two overlapping criteria. First, the neighborhood must be low-income: a poverty rate of 20% or higher, or a median family income at or below 80% of the statewide or metro-area median. Second, a significant portion of residents, at least 500 people or 33% of the population, must live far from the nearest supermarket, supercenter, or large grocery store. In urban areas, “far” means more than 1 mile. In rural areas, it means more than 10 miles. The USDA also tracks a stricter half-mile urban threshold and a 20-mile rural threshold, depending on the measure.
These aren’t arbitrary cutoffs. A mile on foot with grocery bags, no car, and possibly children in tow is a real barrier. And 10 miles in a rural county with no public transit can mean a full afternoon errand just to buy fresh produce.
Redlining Built the Foundation
Many of today’s food deserts map directly onto neighborhoods that were “redlined” in the 1930s. The Home Owners’ Loan Corporation graded urban neighborhoods by perceived mortgage risk, and the lowest grades, C (“declining”) and D (“hazardous”), were assigned overwhelmingly to Black and immigrant communities. Those grades discouraged lending, which starved neighborhoods of investment for decades.
The effects on food access are measurable almost a century later. A national study published in Nature Food found that neighborhoods originally graded D had 149% higher odds of being low-income and low-access today compared to neighborhoods graded A. Even after controlling for additional demographic and economic variables, the association held: D-graded tracts still showed 128% higher odds. The mechanism is straightforward. Redlining depressed property values, drove out businesses, and discouraged new ones from opening. As grocery chains expanded into suburbs in the mid-20th century, restrictive covenants and housing discrimination kept Black residents from following. The supermarkets left, and in many neighborhoods, they never came back.
Grocery Economics Favor Wealthier Areas
Supermarkets operate on thin margins, typically 1% to 3% net profit. That makes site selection extremely conservative. Chains prioritize locations with high traffic, strong purchasing power, and modern building footprints, all of which skew toward newer suburban developments. Low-income urban neighborhoods often have older, smaller retail spaces and lower per-customer spending, which makes them less attractive on paper.
Interestingly, USDA research has found that stores serving low-income customers don’t actually have higher overall operating costs than other stores. Their cost structures differ (lower payroll costs but sometimes higher costs of goods sold), yet the totals come out roughly the same. The barrier isn’t that these stores lose money. It’s that they generate lower total revenue per square foot, which matters to corporate boards comparing potential sites. When a chain can open one store in a high-income suburb or one in a low-income urban core, the suburb almost always wins the internal competition for capital.
Transportation Compounds the Problem
Even where a supermarket exists within a few miles, getting there can be the real obstacle. About 31% of food-insecure households don’t use their own car to shop for groceries. Seventeen percent ride with someone else, and 14% rely on walking, biking, or public transit. For food-insecure households, the average distance to the nearest large grocery store accepting SNAP benefits is 1.85 miles, but the store they actually shop at is 2.82 miles away on average, often because closer options are too expensive or poorly stocked.
People who walk or bike to shop tend to go to stores about 0.9 miles away, even when a SNAP-authorized supermarket sits just half a mile from home. That gap suggests the nearest store doesn’t always meet their needs in terms of price, selection, or quality. Without a car, every grocery trip becomes a calculation of distance, cost, and what you can physically carry home.
Rural Food Deserts Have Different Drivers
In rural America, the problem is less about disinvestment and more about scale and distance. Rural areas have significantly fewer food retailers than urban areas, and lower-income rural households tend to be located even farther from the stores that do exist. The economics are punishing: a small-town grocery store serves a thin customer base spread over a wide area, and distribution costs are higher because suppliers have to truck products longer distances to fewer stops.
Over the past decade, rural food shopping has shifted dramatically. Spending has moved away from independent grocery stores toward two extremes: large supercenters (often requiring a long drive) and small dollar stores. Dollar stores have expanded aggressively into rural communities, and while they provide some food access where nothing else exists, their inventory skews heavily toward shelf-stable, processed items with limited fresh produce. The concern is that dollar stores may undercut the already fragile economics of local grocers, forcing them to close and leaving communities with even fewer healthy options. Grocery industry consolidation adds to this pressure, as regional chains merge and close underperforming rural locations.
Zoning Laws That Block Alternatives
Local zoning codes, often written decades ago, can quietly prevent the kinds of food access solutions that might help. In many cities, zoning prohibits the sale of fruits and vegetables at outdoor stands or markets in residential areas. It can ban community gardens, restrict urban farming, and limit the types of small grocery operations allowed in certain districts. If a use isn’t explicitly permitted in a zoning code, it’s effectively prohibited. That means a neighborhood group that wants to open a farm stand or a small fresh-food market may face a lengthy and expensive rezoning process before they can even start.
Commercial districts are where small grocery stores cluster most heavily, but low-income residential neighborhoods often lack commercial zoning altogether. The result is a regulatory gap: the places that most need food access are zoned in ways that make it hardest to provide.
Food Swamps Make It Worse
Many food deserts are simultaneously “food swamps,” areas flooded with fast-food restaurants and convenience stores relative to healthy food options. Researchers measure this using a ratio of fast-food and convenience outlets to grocery stores and supermarkets. In a national study of over 3,100 U.S. counties, the median food swamp had nearly four unhealthy food outlets for every healthy one. That study found food swamps predicted obesity rates better than food deserts alone, suggesting that the presence of unhealthy options may matter as much as the absence of healthy ones.
This distinction matters because simply dropping a supermarket into a neighborhood doesn’t automatically change eating patterns if residents are still surrounded by cheaper, more convenient fast food on every corner. The food environment is shaped by both what’s missing and what’s flooding in to fill the gap.
Health Consequences Are Measurable
Living without reliable access to nutritious food correlates with higher rates of chronic disease. USDA data from 2019 to 2022 shows that adults in households with very low food security had predicted rates of diabetes, hypertension, coronary heart disease, stroke, and arthritis that were 1.9 to 9.5 percentage points higher than adults in food-secure households. Those gaps are significant at a population level, representing millions of additional cases of preventable disease concentrated in communities that already face the most barriers to healthcare.
The relationship runs in both directions. Chronic disease makes it harder to travel for groceries, harder to prepare meals, and more expensive to manage health, which deepens food insecurity. Neighborhoods with the least access to healthy food often have the highest healthcare costs and the shortest life expectancies, a pattern that traces back through transportation, retail economics, zoning, and decades of structural disinvestment.