Residents of urban food deserts, typically low income neighborhoods, have to deal with limited healthy food choices, in addition to perhaps more obvious disadvantages of life there. A food desert is generally defined as a location where residents have to travel twice as far to get to the nearest supermarket as their peers in wealthier parts of town. A number of recent studies provide data to support the assertion that these residents of food deserts face significant obstacles to the purchase and consumption of affordable healthy food.
Obesity and diet-related diseases are increasingly recognized as major public health problems. Research has suggested that some areas and households have easy access to fast food restaurants and convenience stores but limited access to supermarkets. Limited access to nutritious food and relatively easier access to less nutritious food could be linked to poor diets and, ultimately, to obesity and diet-related diseases. 
Accordingly, in 2008 Congress directed the U.S. Department of Agriculture (USDA) to conduct a 1-year study to assess the extent of the problem of limited access to nutritious food, and to identify its characteristics and causes. The report was completed in June, 2009, and made a number of findings. Results indicated that some consumers had limited ability to access affordable nutritious food, because they lived far from a supermarket or large grocery store and did not have easy access to transportation. 
Nearly 6 percent of all US households did not always have the food they wanted, or needed, because of access-related problems. Nationwide, USDA estimates that 23.5 million people, including 6.5 million children, live in low income areas that are more than a mile from a supermarket. Supermarkets and large grocery stores have lower prices than smaller local convenience stores. People who live in limited access areas often rely on small local grocery or convenience stores, which may not carry all the foods necessary for a healthy diet, and may offer food at higher prices. 
Urban core areas with limited food access are further characterized by higher levels of racial segregation and greater income inequality. More than half of those households who experienced access to food problems also lacked enough money for food. The report found that consumers who shopped at local convenience stores in fact also paid prices that on average were higher than at supermarkets. 
An early study examined the distribution of food stores and food service places by neighborhood wealth and racial segregation in Mississippi, North Carolina, Maryland, and Minnesota. The results of the study, based on 2000 census data, showed that larger numbers of supermarkets and gas stations with convenience stores were located in wealthier neighborhoods, when compared to the poorest neighborhoods. Regarding neighborhood segregation, there were 4 times more supermarkets located in white neighborhoods compared to black neighborhoods. In contrast, however, there were 3 times fewer places to consume alcoholic beverages in the wealthiest areas, when compared to the poorest neighborhoods. 
A 2006 report conducted audits in 2003 and 2004 of community supermarkets and fast food restaurants in St. Louis, Mo., to assess the location and availability of food choices that enable individuals to meet the dietary guidelines established by the U.S. Department of Agriculture (e.g., fruit and vegetable consumption, low-fat options). 2000 census data was used to assess the racial distribution and the percentage of individuals living below the federal poverty level in a defined area of St Louis. 
The report found that two factors, race and income, seemed to be associated not only with the location of food outlets but also with the selection of food available. The data suggested that individuals living in mixed or white high-poverty areas and in primarily African American areas (regardless of income) were less likely to have access to food outlets than individuals in primarily white, higher-income communities. Also, the food available in mixed or white high-poverty areas and in primarily African American areas made it more difficult for individuals to make healthy choices than the food available in primarily white, higher-income communities. 
Another study’s objective was to evaluate food access, availability, and affordability in 3 separate but similar low-income communities in urban Los Angeles, California, during 2004 through 2006. Community members mapped the number and type of retail food outlets in a defined area, and then surveyed a sample of stores to determine whether they sold selected healthful foods and how much those foods cost. Of the 1,273 food establishments mapped in the 3 neighborhoods, the most common types of retail food outlets were fast-food restaurants (30 percent) and convenience/liquor/corner stores (22 percent). Supermarkets made up less than 2 percent of the total. Convenience/liquor/corner stores offered fewer than half of the selected healthful foods and sold healthful foods at higher prices than did supermarkets. The study understandably concluded that access to stores that sold affordable healthful food was a problem in urban Los Angeles communities. 
Another study analyzed in December 2007 and January 2008 the availability and affordability of a healthy market basket in Central Falls, a Rhode Island city in which 40.8 percent of children live in poverty. According to 2000 US census data, 22.8 percent of households in Central Falls had an annual income of less than $10,000, and the median household income was $22,628. Central Falls is also composed of a largely Hispanic community, with 47.8 percent of residents in 2000 identifying as Hispanic or Latino. 21 retail food stores were surveyed, including 9 small grocery stores, 8 convenience stores, 3 bakeries, and 1 meat market. Results established that healthier foods, such as fresh vegetables and meats, were less readily available than most staple foods. The aggregate cost of the tested market basket across all Central Falls retailers was also approximately 41 percent higher when compared to the national average cost of the basket items per week. Again, the report concluded that Central Falls residents had limited access to basic healthy foods, and that those foods, if found, cost more than average. 
Finally, research was conducted in Philadelphia to determine if there was a difference in the microbial quality and potential safety of food available to lower income versus higher income populations at the retail level. Aerobic plate counts, yeast and mold counts, and total coliforms were determined in ready-to-eat greens, precut watermelon, broccoli, strawberries, cucumbers, milk, and orange juice. Results were then compared among products purchased in stores in low income versus those same products purchased in higher income Philadelphia neighborhoods, between June 2005 and September 2006. 
This research found that perishable produce items available in markets in the low income census tracts had higher microbial indicator counts when compared to those in higher income area markets. The authors speculated that small retail facilities that serve populations in lower income urban areas lacked the resources, time, or knowledge to focus on sanitation and proper refrigeration. Small urban retailers may also rely on nontraditional transportation methods that are not refrigerated if they are located in small, inner-city streets. Finally, they may also be a captive market for less quality products from suppliers who have strict quality standards to meet for large corporate retailers. These limitations may contribute to foods being supplied to lower income neighborhoods that have been temperature abused or exposed to unsanitary conditions. 
The available data indicates that residents of these low income urban food deserts have less access to high quality produce, lean meat, and low fat dairy products. They necessarily rely on small markets that primarily sell foods with a long shelf-life, instead of fresh fruits, fresh produce, and low fat foods. These foods, when available, are also apparently more likely to be more contaminated and more expensive.
Food deserts are such important factors in rates of obesity, diabetes, and other illnesses, that Michelle Obama has made access to healthy, affordably-priced groceries one of the cornerstones of her “Let’s Move!” campaign against childhood hunger and obesity. On May 11, 2010, The Task Force on Childhood Obesity Taskforce released its action plan to tackle childhood obesity. Chapter Four of the action plan, “Access to Healthy, Affordable Food”, describes the problem of food deserts, and identifies eleven specific recommendations to reduce the negative impacts on children:
“Healthy options can be hard to find in too many communities. Millions of low-income Americans live in ‘food deserts,’ neighborhoods that lack convenient access to affordable and healthy food. Instead of supermarkets or grocery stores, these communities often have an abundance of fast-food restaurants and convenience stores. In addition, stores in low-income communities may stock fewer and lower quality healthy foods. When available, the cost of fresh foods in low-income areas can be high. Public transportation to supermarkets is often lacking, and long distances separate home and supermarkets in many rural communities and American Indian reservations. It is hard for residents of these areas–even those fully informed and motivated–to follow the necessary and recommended steps to maintain a healthy weight for themselves and their children. Too often, economic incentives strongly favor unhealthy eating, and accessibility, safety concerns, and convenience can also promote unhealthy outcomes.
“Limited access to healthy food choices can lead to poor diets and higher levels of obesity and other diet-related diseases. In addition, limited access to affordable food choices can lead to higher levels of food insecurity, increasing the number of low- and moderate-income families without access to enough food to sustain a healthy, active life. There is a growing, though incomplete, body of research that finds an association between food insecurity and obesity, suggesting that hunger and obesity may be two sides of the same coin.” 
The Action Plan then makes the following recommendations, to be implemented as soon as possible:
Recommendation 4.1: Launch a multi-year, multi-agency Healthy Food Financing Initiative to leverage private funds to increase the availability of affordable, healthy foods in underserved urban and rural communities across the country.
Recommendation 4.2: Local governments should be encouraged to create incentives to attract supermarkets and grocery stores to underserved neighborhoods and improve transportation routes to healthy food retailers.
Recommendation 4.3: Food distributors should be encouraged to explore ways to use their existing distribution chains and systems to bring fresh and healthy foods into underserved communities.
Recommendation 4.4: Encourage communities to promote efforts to provide fruits and vegetables in a variety of settings and encourage the establishment and use of direct-to-consumer marketing outlets such as farmers’ markets and community supported agriculture subscriptions.
Recommendation 4.5: Encourage the establishment of regional, city, or county food policy councils to enhance comprehensive food system policy that improves health.
Recommendation 4.6: Encourage publicly and privately-managed facilities that serve children, such as hospitals, after school programs, recreation centers, and parks (including national parks) to implement policies and practices, consistent with the Dietary Guidelines, to promote healthy foods and beverages and reduce or eliminate the availability of calorie-dense, nutrient-poor foods.
Recommendation 4.7: Provide economic incentives to increase production of healthy foods such as fruits, vegetables, and whole grains, as well as create greater access to local and healthy food for consumers.
Recommendation 4.8: Demonstrate and evaluate the effect of targeted subsidies on purchases of healthy food through nutrition assistance programs.
Recommendation 4.9: Analyze the effect of state and local sales taxes on less healthy, energy-dense foods
Recommendation 4.10: The food, beverage, and restaurant industries should be encouraged to use their creativity and resources to develop or reformulate more healthful foods for children and young people.
Recommendation 4.11: Increase participation rates in USDA nutrition assistance programs through creative outreach and improved customer service, state adoption of improved policy options and technology systems, and effective practices to ensure ready access to nutrition assistance program benefits, especially for children.
”Access to Affordable and Nutritious Food: Measuring and Understanding Food Deserts and Their Consequences”, United States Department of Agriculture, Economic Research Service, June 2009.
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Baker EA, Schootman M, Barnidge E, Kelly C. “The role of race and poverty in access to foods that enable individuals to adhere to dietary guidelines”. Prev Chronic Dis, 2006 Jul.
Azuma AM, Gilliland S, Vallianatos M, Gottlieb R. “Food access, availability, and affordability in 3 Los Angeles communities, Project CAFE, 2004-2006”. Prev Chronic Dis 2010 Mar;7:A27.
Sheldon M, Gans KM, Tai R, George T, Lawson E, Pearlman DN. “Availability, affordability, and accessibility of a healthful diet in a low-income community, Central Falls, Rhode Island, 2007-2008”. Prev Chronic Dis 2010;7.
Marlen E. Koro, MS, Shivanthi Anandan, PhD, Jennifer J. Quinlan, PhD, “Microbial Quality of Food Available to Populations of Differing Socioeconomic Status”, Am J Prev Med, May, 2010.
”Solving the Problem of Childhood Obesity”, Task Force on Childhood Obesity, Action Plan, May 2010.