Advertising by chain restaurants was associated with modest weight gain in adults living in low-income areas, according to a longitudinal cohort study.
The study followed nearly 6 million U.S. adults for 4 years and found that each $1 per-capita increase in quarterly advertising spending was linked with a 0.053-unit increase in body mass index (BMI) for those living in low-income counties (95% CI 0.001-0.102), said researchers led by Sara Bleich, PhD, of the Harvard T.H. Chan School of Public Health in Boston.
Writing online in JAMA Network Open, Bleich’s group said they found no significant association overall, when counties at all levels of income were included. However, the researchers reported that BMI rose by 0.12% in counties where advertising spending increased the most, compared with a 0.12% drop in BMI in counties with the greatest decrease in spending.
Previous studies have explored links between restaurant advertising and obesity in children, but data are lacking in adults, Bleich and colleagues said. “Examined alongside previous research showing that unhealthy food and beverage marketing is associated with higher obesity risk in youth, our findings suggest that public policies or initiatives or private sector actions would help reduce the negative impacts of exposure to restaurant advertising across the population,” they wrote. “These results specifically point to the potential benefits from reduced exposure to restaurant advertising among adults with low incomes.”
The link between restaurant advertising and weight gain for people in low-income counties could be explained by less-healthy foods and beverages being marketed to this group, the researchers suggested. “This explanation is consistent with prior evidence indicating that advertisements for unhealthy items are often targeted toward those at higher risk for obesity, and unhealthy food retail outlets, such as fast food restaurants, are more densely located in low-income and minority communities,” they noted.
A previous study reported that exposure to food ads, particularly for sugary beverages and fast food restaurants, is significantly higher among youth in communities with higher proportions of Black families and lower-income families, Bleich’s group said. Another study found that targeted TV marketing of food and beverages toward Black and Hispanic children were for products high in fat or sugar, they noted.
“The findings of this study are concerning because they suggest that restaurant advertising spending targeted toward low-income communities may contribute to the observed disparities in obesity,” they wrote.
Lauri Wright, PhD, director of the clinical nutrition program at the University of North Florida in Jacksonville, and who was not involved in the study, agreed with the researchers.
“It is well established that restaurant dining can be fraught with calories, fat and sodium,” she wrote in an email to MedPage Today. “You may infer that lower income groups may be dining at lower cost restaurants such as fast-food restaurants, where it is even more challenging to make healthy food choices.”
“These findings really speak to perpetuating health disparities among our low-income, probable food-insecure population,” she said. “It also calls for public policy initiatives to limit restaurant advertising among low income populations.”
Bleich and colleagues analyzed data on 5,987,213 U.S. adults age 20 or older obtained from Athenahealth, who lived in 370 counties across 44 states. They tended to be older (37% were older than 60), and slightly more than half (56.8%) were women. During the 4-year study period, the mean BMI was 29.8, which is considered overweight. The height and weight used to calculate BMI were measured at clinic visits.
The researchers obtained data from Kantar Media on quarterly advertising spending for 66 of the largest U.S. chain restaurants from 2013 to 2016. Overall restaurant advertising per capita was a mean $4.72 per quarter, and spending was higher in low-income counties compared with high-income counties ($4.95 vs $4.50 per quarter). The majority of this spending was on television advertising for fast food restaurants.
The associations in the study appeared to be driven by both full-service and fast food restaurants, as well as television marketing, the researchers said. They observed significant associations with BMI for restaurant advertising among all media types for full-service restaurants and fast food restaurants (point estimate 0.145, 95% CI 0.06-0.23); television advertising only for all types of restaurants (point estimate 0.057, 95% CI 0.0002-0.11); and TV ads only for fast food and full-service restaurants (point estimate 0.141, 95% CI 0.05-0.23).
The researchers noted some limitations to their study. Their sample represented only adults who were engaged with the healthcare system, and the majority were white (only 12% were non-white). In addition, fewer than 30% of participants were younger than 40. Finally, the study did not take into account the overall diet or physical activity of participants, they said.
“In conclusion, the present study found that restaurant advertising was associated with modest weight gain among adults in low-income counties — communities which are often exposed to disproportionately more advertising for unhealthy menu items and which are composed of individuals at higher risk for obesity,” they wrote. “Efforts to decrease the promotion of unhealthy menu items targeting low-income communities should be intensified to help attenuate the association of restaurant advertising with obesity risk among vulnerable populations.”
Last Updated October 07, 2020
The study was supported by Health Data for Action, a program of the Robert Wood Johnson Foundation. No authors reported relevant conflicts of interest.