To provide a richer understanding of food access and purchasing practices among US urban food desert residents and their association with diet and BMI.

Data on food purchasing practices, dietary intake, height and weight from the primary food shopper in randomly selected households (n 1372) were collected. Audits of all neighbourhood food stores (n 24) and the most-frequented stores outside the neighbourhood (n 16) were conducted. Aspects of food access and purchasing practices and relationships among them were examined and tests of their associations with dietary quality and BMI were conducted.

Two low-income, predominantly African-American neighbourhoods with limited access to healthy food in Pittsburgh, PA, USA.

Household food shoppers.

Only one neighbourhood outlet sold fresh produce; nearly all respondents did major food shopping outside the neighbourhood. Although the nearest full-service supermarket was an average of 2·6 km from their home, respondents shopped an average of 6·0 km from home. The average trip was by car, took approximately 2 h for the round trip, and occurred two to four times per month. Respondents spent approximately $US 37 per person per week on food. Those who made longer trips had access to cars, shopped less often and spent less money per person. Those who travelled further when they shopped had higher BMI, but most residents already shopped where healthy foods were available, and physical distance from full-service supermarkets was unrelated to weight or dietary quality.

Improved access to healthy foods is the target of current policies meant to improve health. However, distance to the closest supermarket might not be as important as previously thought, and thus policy and interventions that focus merely on improving access may not be effective.