For years, public health researchers have used the term “food desert” to describe neighborhoods where residents struggle to access nutritious food. The assumption has been simple: if there’s no grocery store nearby, people eat less healthy diets. But a new study from the University of Adelaide suggests that the real story is more complicated and that solving nutrition gaps will require more than building supermarkets.
The study, published in PLOS Complex Systems, analyzed food purchase records from 1.6 million customers at Tesco, one of the United Kingdom’s largest grocery chains. By examining what shoppers actually bought, the research team identified neighborhoods in London where residents’ purchases reflected nutrient-deficient patterns, even when stores selling healthy foods were close by.
“Food deserts refer to areas where residents are unable to access a nutritious diet, where barriers to obtaining healthy foods are thought to underpin dietary behavior,” said Tayla Broadbridge from the University’s School of Computer and Mathematical Sciences, who led the study. “Previous attempts to identify food deserts have relied on assumptions about the relationships between store locations, sociodemographic factors and access to healthy food.”
The new approach adds something those earlier studies lacked: real purchase data.
“Treating food access as only a store distribution problem ignores critical factors such as cultural and economic landscapes that shape residents’ urban life and mobility, and, consequently, their shopping behavior,” Broadbridge said.
By linking transaction data with neighborhood demographics, the researchers found that nutritional disadvantage was concentrated in low-income and minority communities, even in areas with supermarkets nearby. In East London, including Newham, Barking and Dagenham, shoppers were more likely to buy high-sugar and high-carbohydrate foods. Similar patterns appeared in parts of northwest London, such as Ealing and Brent.
“The strong variation in these relationships across London’s neighborhoods highlights the need for locally tailored, culturally sensitive strategies to improve access to healthy food,” Broadbridge said.
She noted that applying this method elsewhere could help cities better understand how social and economic factors shape shopping behavior and diet quality.
Although this research focused on London, the team believes it could be replicated in other countries using data from major grocery retailers.
“This study moves beyond the reliance on sociodemographic and environment characteristics alone when identifying food deserts,” Broadbridge said. “Our method could use loyalty card data from major grocery retailers such as Woolworths or Coles to show where nutritional disadvantage is most concentrated, and how it relates to local sociodemographic factors.”
The findings point to an uncomfortable truth: access to healthy food isn’t just about having stores nearby; it’s about who can afford nutritious choices and how culture, income and marketing shape what ends up in the basket.
The authors reported no specific funding for this work.