Over the past 2 decades, studies have been replicated, providing evidence that there are disparities in the placement of supermarkets in the United States and that these disparities have an impact on the nutritional choices of Americans. This knowledge is robustly supported by variation in the population samples surveyed, the location of geographic areas studied, and the methods used to measure diet and local food environments. Boone-Heinonen et al1 have recently contributed to this growing area of science with a study design aimed to measure causation with a longitudinal reconstruction of food environments for a young adult population. The authors' negative findings between supermarket availability and diet quality are inconsistent with previous studies.