Past studies have suggested a relationship between
neighborhood characteristics and obesity, as well as a connection between
obesity and advertisements on television and in magazines.
Now, new research from UCLA has identified a possible link between outdoor
food ads and a tendency to pack on pounds. The findings, researchers say, are
not encouraging.
Researchers suggest that the more outdoor advertisements promoting
fast food and soft drinks there are in a given census tract, the higher the
likelihood that the area’s residents are overweight.
“Obesity is a significant health problem, so we need to know
the factors that contribute to the overeating of processed food,” said Lesser,
who conducted the research while a Robert Wood Johnson Foundation Clinical
Scholar at the UCLA Department of Family Medicine and UCLA’s Fielding School of
Public Health.
“Previous research has found that fast food ads are more
prevalent in low-income, minority areas, and laboratory studies have shown that
marketing gets people to eat more,” said Lesser, now a research physician at
the Palo Alto Medical Foundation Research Institute in California. “This is one
of the first studies to suggest an association between outdoor advertising and
obesity.”
For the study, the researchers looked at two densely
populated areas in Los Angeles and New Orleans, each with more than 2,000
people per square mile. They focused on more than 200 randomly selected census
tracts from those two areas, which included a mixture of high- and low-income
residents.
The team used data on outdoor food advertising in those
areas gleaned from a previous study on ads and alcohol consumption (which had
tracked all the outdoor ads). They then linked that information with
telephone-survey data from the same study, in which nearly 2,600 people between
the ages of 18 and 98 from those areas were asked health-related questions in
addition to questions about their height, weight, self-reported body mass index
(BMI) and soda consumption.
The researchers found a correlation: The higher the
percentage of outdoor ads for food, the higher the odds of obesity in those
areas.
“For instance, in a typical census tract with about 5,000
people, if 30 percent of the outdoor ads were devoted to food, we would expect
to find an additional 100 to 150 people who are obese, compared with a census
tract without any food ads,” Lesser said.
Given that the study focused on only two areas, the authors
urge further research to determine if the findings would be replicated in other
areas. Because the study was cross-sectional, the researchers do not claim that
the ads caused the obesity. They also note that self-reported information about
weight is subject to recall bias, and people often under-report their true
weight.
But this study suggests enough of a link between outdoor
food advertising and “a modest, but clinically meaningful, increased likelihood
of obesity” to warrant further examination, the researchers conclude.
“If the … associations are confirmed by additional research,
policy approaches may be important to reduce the amount of food advertising in
urban areas,” the researchers write, while noting that outright bans on such
ads might be deemed unconstitutional. “Innovative strategies, such as warning
labels, counter-advertising, or a tax on obesogenic advertising should be
tested as possible public health interventions for reducing the prevalence of
obesity.”
