"Researchers compared access to supermarkets, smaller grocery stores, and convenience stores in largely black, Latino, white and racially integrated neighborhoods in a national sample of more than 65,000 census tracts. Earlier research showed that convenience stores and groceries, which are smaller than supermarkets, stock foods higher in fat, sugar and salt.

The study found that living in a poor, mostly black neighborhood presented "a double disadvantage" in supermarket access. Unsurprisingly, poor black neighborhoods had fewer supermarkets than wealthier black neighborhoods."

http://articles.latimes.com/2013/oct/30/science/la-sci-sn-po...