This article is more than 1 year old

This article is more than 1 year old

Fast-food outlets along commuter routes could be contributing to the obesity crisis, research suggests.

A study by a US academic found that a greater density of fast-food outlets on commuter routes is linked to higher body mass index (BMI) scores among those travelling along them.

Prof Adriana Dornelles, the author of the research from Arizona State University, said the study showed fast-food outlets were taking their toll on the waistlines of Americans.

“After a long day at work the last thing that you are going to think about is [going] home and [preparing] a meal,” she said.

Writing in the journal Plos One, Dornelles reports how she carried out her research using data from 710 female employees at 22 schools in New Orleans, together with maps of food outlets and census data.

Dornelles looked at the type of food outlets within 1km of the employees’ home and work addresses, as well as within 1km of the shortest commute routes between the two, as calculated for each participant.

After taking into account factors including physical activity, ethnicity and household income, Dornelles found that the presence of greater numbers of supermarkets and grocery stores near commuters’ homes was linked to higher BMI scores – something she puts down to many grocery stores offering little fresh produce but lots of frozen foods and snacks.

The results held even when the presence of such shops near work or along the commuter route was taken into account. However, a greater number of “full-service” restaurants near home addresses was linked to a lower BMI – possibly, says Dornelles, because they offer healthy meals.

Greater density of fast-foods outlets in the 1km around the shortest commuter route was also linked to higher BMI: for every extra fast-food outlet per kilometre of the commute, employees’ BMI was 0.7 units higher on average. The results were similar when fast-food outlets near home and work were also taken into account.

The number and types of food outlets near schools were not linked to BMI – perhaps because teachers and other school employees usually eat lunch at school.

“Public policies are needed to either prevent the increase of fast-food retailers or encourage small business to use the same fast-food business model, quick-cheap-easy, but offering healthier food options,” said Dornelles.

However, the study has limitations: it does not prove that the presence of fast-food outlets drives a higher BMI, while the study is only based on data from women, the majority of whom were white and middle-aged. In addition, commuter routes were hypothetical.

Steven Cummins, a professor of population health at the London School of Hygiene and Tropical Medicine said the study was interesting, but noted it did not consider whether participants were seeking fast food from further afield or having it delivered, or whether participants were actually buying fast food.

The research is the latest in a string of studies looking at the availability of junk food and the impact on health – with such outlets thought to contribute to an “obesogenic” environment. However, the picture is far from clear.

Research from the University of Cambridge has previously found that those with greater exposure to fast-food outlets – based on a combination of where they live, work and commute – were more likely to eat it and have a higher BMI, together with a greater likelihood of being obese.

However not all studies show a link between presence of local fast-food outlets and BMI.

Fast food England: how many takeaways are near you? Read more

Public Health England’s guidance on different actions that could be taken by local authorities and others to tackle obesity includes restricting growth in the number of fast-food outlets through the planning system.

Data from PHE shows the wealthiest 10% of the country has just 3% of the total number of fast-food outlets while the poorest 10% of the country has 17% of such outlets.

Some parts of the country have long adopted such ideas: in 2010 Barking and Dagenham became the first UK council to tackle the availability of fast food, although by 2017 there was little sign that the efforts were having a positive impact on the waistlines of locals, with 42.2% of 11-years olds overweight or obese.

Ian Hudspeth, the chairman of the Local Government Association’s community wellbeing board, said councils were embracing a range of measures including restrictions on takeaways and helping businesses create healthier menus. But he said they needed more support – including a reversal of public health funding cuts.

“Numerous councils have set curbs on new fast-food outlets but current legislation means they lack planning powers to tackle the clustering of existing takeaways already open,” he added.

Cummings said there are many factors besides the location of fast-food outlets that might be contributing to the expansion of waistlines – including portion sizes, advertising and price promotions.

“There is no single magic bullet. Rather we need to tackle the multiple influences on diet and obesity from the individual level to the whole population all at the same time,” he said. “Only by tackling this complex system of influences on behaviour can we perhaps start to tackle the obesity epidemic.”