Activity space-based measures of the food environment and their relationships to food purchasing behaviours for young urban adults in Canada.

Objective: To examine the potential links between activity spaces, the food retail environment and food shopping behaviours for the population of young, urban adults.

Design: Participants took part in the Canada Food Study, which collected information on demographics, food behaviour, diet and health, as well as an additional smartphone study that included a seven-day period of logging GPS (global positioning system) location and food purchases. Using a time-weighted, continuous representation of participant activity spaces generated from GPS trajectory data, the locations of food purchases and a geocoded food retail data set, negative binomial regression models were used to explore what types of food retailers participants were exposed to and where food purchases were made.