A 2009 study by the Department of Agriculture found that 2.3 million households do not have access to a car and live more than a mile from a supermarket. Much of the public health debate over rising obesity rates has turned to these "food deserts," where convenience store fare is more accessible--and more expensive--than healthier options farther away. This map colors each county in America by the percentage of households in food deserts, according to the USDA's definition.
