Food deserts driven by inequality, shows purchasing data from Tesco

A study using purchasing data from Tesco to map areas in London, England, has identified areas where residents’ diets are nutritionally inadequate, leading to “food deserts.” It found that financial and social inequality is the primary driver, rather than physical distance to stores.  

Certain areas showed higher adherence to high-sugar and high-carbohydrate purchases, indicating food deserts — areas where residents are unable to access healthy diets.  

The researchers say previous attempts to identify food deserts have been based on store locations, sociodemographic factors, and access to healthy foods.

“We are re-thinking urban food deserts: purchase data, not supermarket locations, shows the reality of access to healthy food in London. A map of food stores only shows potential access — food purchase data shows the reality, revealing where Londoners’ diets are nutritionally deficient,” says Tayla Broadbridge, lead researcher and Ph.D. student from the School of Mathematics, a part of the University of Nottingham, UK.

The study researchers from the University of Nottingham stress that poor diets and nutrition account for 13% of deaths in the UK, and are a global health risk. Meanwhile, 61% of London’s population has been classified as overweight or obese in recent years. Children in London also have a higher rate of being overweight compared to other cities in England. 

A previous report published in The Lancet revealed that obesity is becoming the most common form of malnutrition in many countries, and obesity rates among children have increased by four times in the last 33 years. 

The new study attributes these changes to the increased production of processed foods, changing lifestyles, and rapid urbanization.

“Our findings emphasise the need for targeted interventions that address local food access issues according to specific socioeconomic characteristics. To be effective, interventions should be strategically targeted to areas that show nutritionally deficient purchasing behaviors, and with sociodemographic characteristics in mind,” adds Broadbridge.

Clusters of food deserts

The study, published in PLOS Complex Systems, says that food purchasing patterns vary geographically across different neighborhoods in London. 

The study investigated data from 1.6 million Tesco customers in London.It investigated data from 1.6 million Tesco customers in London, and examined purchasing patterns between high-sugar and carbohydrate foods, compared to those high in fiber and protein. 

The foods and beverages were divided into 12 categories: grains, fruit and vegetables, fish, red meat, poultry, eggs, dairy, fats and oils, sauces, ready meals, sweets, and soft drinks. 

By investigating purchasing patterns, the researchers could determine urban health challenges. They identified both the drivers of food deserts and pinpointed their actual locations, finding that nutritionally deficient purchasing power was strongly clustered geographically.

Food deserts were mainly found in East and West London, while the central and inner-west of London showed “food oases” — residents purchase more nutritious foods. 

Meanwhile, the study also pinpointed sociodemographic differences — such as low income and higher proportions of Black, Asian, and minority ethnic residents — being the highest predictor of food desert areas. 

A surprising find, according to the researchers, was that higher car ownership was associated with poor nutritional purchases, which may be attributed to car-dependent lower-income areas, rather than access to nutritious food.

Walking time to stores had little impact, leading the researchers to suggest that in urban dense cities such as London, physical distance to stores is overruled by economic and cultural factors. 

“A ‘one-size-fits-all’ approach is not the most effective way of addressing food deserts in London, and interventions should be tailored to the local level to maximize the effectiveness and compliance,” concludes Broadbridge.