Wal-Mart stores. Recently, Appetite for Profit writer Michele Simon went head-to-head with the study I quoted in the above link, saying that a recent study by Loyola University showed that agglomeration did not, in fact, occur when Wal-Mart moved to Chicago. In fact, the study found that "the weight of evidence suggests that the Wal-Mart opening on the West Side led to the displacement of a range of businesses. There is no evidence that Wal-Mart sparked any significant net growth in economic activity or employment in the area."
That being said, the study does not find a specific relationship between the closing of food stores and the opening of a Wal-Mart - so, setting aside for the moment the issue of economic development, does it mean that a Wal-Mart can still have a positive impact on the diet of its neighbors? Not necessarily, says a study published in the Archives of Internal Medicine and reported in the Los Angeles Times. While access to fast food does measurably increase consumption of fast food, "Greater supermarket availability was generally unrelated to diet quality and fruit and vegetable intake, and relationships between grocery store availability and diet outcomes were mixed."
According to a published comment on the study by Jonathan E. Fielding, M.D., M.P.H., and Paul A. Simon, M.D., M.P.H., from the Los Angeles County Department of Public Health and the University of California, Los Angeles "In many disadvantaged communities, the food environment is more swamp than desert, with a plethora of fast food; convenience stores selling calorie-dense packaged foods, super-sized sodas, and other sugar-loaded beverages; and other nonfood retail venues selling junk food as a side activity." They suggest that public policy restricting access to junk foods may be more effective than increasing access to healthy foods.