Islands in an Obesogenic Ocean: A Multiscale Spatial Analysis of School Neighborhood Food Environments in Michigan

This study examines the retail food environment surrounding public schools in Michigan using a multiscale, multidimensional framework. A cross-sectional spatial analysis integrates relative healthfulness (modified Retail Food Environment Index, mRFEI), availability (outlet density), and accessibility (network-based walking time) across school districts, census tracts, block groups, and school-centered buffers. The analysis includes 3,530 public schools, 7,680 fast food restaurants, and 2,065 convenience stores. Results show pronounced spatial heterogeneity and clustering of unhealthful outlets (Nearest Neighbor Index = 0.284, p < 0.001), with many located near schools. Approximately 34% of schools are within a 10-minute walk of a fast food restaurant, increasing to 65% within 20 minutes. Urban schools face significantly higher exposure—2.27–2.80 times more fast food outlets and shorter walking times than rural schools (p ≤ 0.002)—with consistent gradients across city, suburban, town, and rural contexts. Overall, school neighborhood food environments are highly structured, obesogenic, and inequitable. By integrating multiple spatial scales and dimensions, this study advances food environment research and provides policy-relevant evidence for targeted, place-based interventions to improve access to healthier food around schools.