How Distance Decay Effects Shape Accessibility of Food Provided by Online Food Delivery Services: Evidence from Two Chinese Megacities

Ensuring adequate access to healthy food is essential for public health. As a rapidly growing food access channel, online food delivery (OFD) services have gained widespread popularity globally, particularly in China. The accessibility of food through OFD retailers remains underexplored, however. This study addresses this gap by analyzing comprehensive data sets of 129,140 OFD retailers and 240,455 offline food retailers across ten categories in two Chinese megacities (Shenzhen and Wuhan). We estimated the service area sizes (distance decay effects) of all retailers and systematically evaluated OFD and offline food accessibility in terms of total accessibility levels, spatial inequities, categorical distributions, and market shares. The results highlight significant differences between OFD and offline food accessibility patterns, driven by distinct service area structures. Offline food retailers have a three-level hierarchical structure. A few retailers at the upper level and middle-level hierarchies have large service area sizes, whereas a huge number of retailers at the lower level hierarchy have small service area sizes. By contrast, service area sizes of all OFD retailers are equalized by enlarging those of lower level retailers and reducing those of middle-level and upper level retailers. The results of this study deepen our understanding of how OFD services alter the distance decay effects of food retailers, and how these effects shape accessibility to food retailers of various categories, including healthy and unhealthy food retailers, as well as restaurants.