People whose work commute takes them along a route with plenty of fast-food restaurants tend to have a higher body mass index (BMI) than their co-workers whose commute is free of such establishments, according to a study published this week in the journal PLOS One.
This finding underscores the role that “built environments” — the structures and features in our communities — play in the obesity epidemic.
“In our daily lives, we are exposed to several healthy and unhealthy food choices, which has an impact on BMI,” said Adriana Dornelles, the study’s author and an economist at Arizona State University, in a released statement. “The availability and variety of fast food restaurants along our commute create endless opportunities for a quick, cheap, and unhealthy meal.”
But, interestingly — and surprisingly — the study also found that commuters who had a significant number of large supermarkets and small grocery stores near their homes tended to have higher BMIs.
That finding suggests that commuters are choosing high-calorie junk or processed foods for their meals even when other options are available — perhaps because they are too tired or too short of time to prepare a healthier meal at home.
How the study was done
For the study, Dornelles analyzed data from 710 women employed in various jobs at 22 elementary schools in New Orleans. The data had been collected as part of a wellness intervention program for school personnel. It included the women’s BMI, a metric generally used (although not without some controversy) to determine whether a person is overweight or obese. The data also included the women’s home addresses.
Dornelles used those addresses to map the shortest commuting route (by car) between the women’s home and the school where they worked. She then counted the number of supermarkets, small grocery stores, fast-food restaurants and full-service restaurants within a 1-kilometer radius of the women’s home and workplace, as well as along the most direct route between the two.
With that data in hand, Dornelles looked for links between the women’s BMI and the density of food establishments around all three environments — home, workplace and commuting route. She first, however, adjusted the data for other factors associated with BMI, such as physical activity, occupation, race/ethnicity and household income.
That adjusted data revealed the following:
- The school employees whose commuting routes were lined with the most fast-food restaurants tended to have higher BMIs.
- The employees who had a greater number of fast-food restaurants as well as supermarkets and smaller grocery stores around their homes also tended to have higher BMIs.
- Having lots of food outlets (including fast-food restaurants) near the women’s workplaces was not associated with higher BMIs. That may be because “school personnel have limited time for lunch, which might restrict their access to food retailers outside the school,” Dornelles explains in her paper.
- The school employees who had a higher density of full-service restaurants near their homes tended to have lower BMIs (Dornelles doesn’t speculate on possible reasons for this finding.)
Limitations and implications
The study comes with plenty of caveats. To begin with, it is an observational study and therefore can’t prove a relationship between food outlets and BMIs. In addition, the study involved a relatively small number of participants, all of whom were women and living in one geographical area. The findings might be different if a larger, more diverse group of people had been studied.
Furthermore, Dornelles only guessed at the school employees’ commuting routes. Nor was she able to determine if the participants actually stopped to purchase foods along those routes.
Still, the findings are in line with other research that has suggested a relationship between a neighborhood’s food outlets and its residents’ weight. What’s new about this study, however, is that it found a similar relationship with the types of food establishments along our commuting corridors.
You may want to keep that in mind the next time you stop to pick up “something for dinner” on your way home from a long, hard day at work.
FMI: You can read the study in full on the PLOS One website.