Study reveals daily food environment exposure shapes fast food habits

By Dr. Liji Thomas, MDReviewed by Benedette Cuffari, M.Sc.Mar 18 2024

A recent study published in the journal Nature Communications examines how dietary choices are influenced by exposure to food outlets throughout the day.

Study: Effect of mobile food environments on fast food visits. Image Credit: Alena Haurylik / Shutterstock.com

Diet and illness

The advent of readily available, inexpensive, and unhealthy fast foods has adversely affected diet quality. Fast foods are typically energy-dense but provide little nutrition.

In 2017, poor diet led to 11 million deaths, thus surpassing tobacco-related mortality. Many of these deaths can be attributed to obesity, type 2 diabetes, cardiovascular disease, and certain cancers.

Food swamps and food deserts

People exposed to or spend time in low-quality food environments tend to have worse diet quality. These environments can be classified as food deserts or food swamps.

Whereas food deserts refer to areas where it is difficult to access healthy foods, food swamps have a high ratio of food outlets and convenience stores that offer unhealthy food, including fast food. Both food deserts and food swamps are more often found in low-income communities and those of color in the United States.

Food deserts reduce access to a quality diet, as many people in these areas will have to travel over half a mile to a supermarket, the generic source of healthy, inexpensive food. Living in a food swamp promotes unhealthy food consumption due to the availability of cheap junk food promoted by social cues and neighborhood structures.  

Mobility and food choices

Local static food outlets near homes, schools, and workplaces have not been consistently associated with an increased likelihood of an unhealthy diet. Nevertheless, various policies have been passed in an effort to support healthy food environments, especially in underserved areas, as well as fast food bans in some Los Angeles neighborhoods.

Despite these initiatives, half of the money spent on food in the U.S. is spent away from home, mostly on fast food and full-service restaurants, which amounts to one-third of the energy intake.

Study aim

The current study explores how often people visit food outlets in and outside of their home neighborhood over a six-month period, with these visits correlated with their exposure to mobile food environments. The emphasis was on fast food outlet (FFO) visits, as previous research has demonstrated a link between fast food consumption and nutritional health.

Food outlet vs FFO visits

Less than 8% of FFO visits were in the locality of home, with the median distance to the supermarket visited about three kilometers (km) as compared to seven kilometers to the food outlet or FFO. Notably, the study participants were exposed to different food environments during the day than those present around their homes.

About 13% of food outlet visits were to FFOs; however, almost 23% of the population never visited an FFO during the study. There was a low correlation with sociodemographic characteristics.

Most visits for food are between lunchtime and dinner time, including those to FFOs; however, peak visit times to FFOs are around lunchtime. Time constraints might play a significant role in such decisions.

An individual’s exposure to FFO across the day, rather than within their home environment, is a more important driver of the decision to get fast food.”

A second analysis of food outlet choices was performed at randomized locations, including only people who visited the Department of Motor Vehicles (DMV), many of whom would have to leave their neighborhood to do so. This analysis adjusted for the effects of income and food preferences, thereby confirming the influence of the environment on FFO visits.

The power of habitual choice

People who shifted from a high-to-low-FFO mobile environment reduced their visits from about 24% to 15%; however, the opposite and equal shift occurred among those who changed from a low-to-high-FFO context from 16% to 25%. Those who changed their food contexts but with the same proportion of FFOs did not show any change in the frequency of visits.

This effect persisted, even 50 days after the change, thus indicating a strong role for habitual exposure to a food environment beyond visiting a new place.

Sociodemographic factors

Study participants exposed to relatively FFO-rich mobile environments lived in areas with higher Black representation, with more individuals who commute longer distances, have lower-skilled jobs, are less educated, and use public transportation. People from these neighborhoods visited FFOs more frequently.

Conversely, the home neighborhoods of areas with more FFOs are more likely to have more educated but lower-income individuals with jobs closer to home. Overall, the social and demographic characteristics of the individual are more closely related to their mobile food environment than the home food environment. 

Potential interventions

Multiple strategies are possible at the policy level, including banning or reducing the number of FFOs compared to other food outlets, increasing the number of other food outlets, and changing an FFO to a healthy food outlet.

By modeling the effects of changes in FFO number and ratio, as well as areas where food choices are made most frequently, the researchers examined the Food Swamp, Low Food Access, and Food Hotspots interventions. Despite including hotspots like restaurants or entertainment spots, these models are less likely to be effective, as people here are less affected by the environment.

The Behavior-Environment model includes individual preferences and exposures to mobile food environments, modifications in the spatial and temporal environment, and individual behaviors. This model is predicted to be two to four times more efficient in reducing FFO visits than the other interventions.

The Behavior-Environment intervention could avert around 719k visits to FFO in 6 months, compared with only 442k at most in the other interventions.”

This impact is independent of income, health status, or city of residence. Even in a high-risk group, such as those who are obese or have type 2 diabetes, the impact remains more than double that of any other intervention.

What are the conclusions?

Better initiatives to improve food environments should consider food hotspots and mobile food environments that people are exposed to throughout the day. Furthermore, the historical inequities between different socioeconomic groups in food environments must be considered while designing any intervention.

Interventions at the individual level could also be modified based on these methods, such as promoting visits to healthy food outlets through mobile apps.

The current large study was based on mobility data collected from nearly 1.9 million users in 11 metropolitan areas in the U.S., yielding 62 million visits to food outlets. This approach confirms the utility of these data in observing behavioral choices in the context of daily routines. Nevertheless, further studies are needed to validate and extend these findings.