Proximity to fast food and convenience stores puts children at higher risk of being overweight or obese, according to a new study led by researchers at New York University School of Medicine and published Tuesday in the journal Obesity.
More than 1 million children attend New York City public schools. How close they live to a fast-food restaurant can have a direct impact on their chances of becoming obese, researchers found. The research team, led by Brian Elbel, found that 20% of children between the ages of 5 and 18 living within a half-block of a fast-food outlet were obese and 38% were overweight.
The obesity figures dropped for every half block farther away that students lived from unhealthy food sources, the researchers found.
Elbel said in a phone interview that the findings showed a new impact of "the potential role of the food environment" on public health.
Since 2007, schools in New York have tracked students' height and weight. Elbel and his team used mapping software and the city's restaurant inspection data to compare students' addresses with their distance from fast-food outlets, corner stores, sit-down restaurants and grocery stores, all selling healthy food and junk food.
The researchers used the inspection data to identify restaurants with counter service, including pizza, Chinese and any other kind of order-at-the-counter takeout.
The researchers were then able to correlate students' body mass index data with precisely how close they lived to these kinds of restaurants.
The comparisons made were "highly neighborhood specific," according to the researchers. For example, youths in a small section of Harlem were compared only with other youths in the same part of Harlem.
"It really gets rid of a lot of the confounding data like socioeconomic status," Elbel said. "We weren't looking at Upper East Side kids versus Lower East Side kids. We were comparing kids that live in the same small neighborhood to each other. How does living close versus a little bit further away affect kids? There's something about living within half a block to fast food that's not great."
The study, Elbel acknowledged, does not account for the rise of healthier counter-service eateries such as Sweetgreen, but he said that because the data was collected between 2007 and 2013, most of the eateries covered by the study were traditional fast-food restaurants leaning on hamburgers, sandwiches and such.
For Elbel, "food swamps," or urban areas with a density of fast-food restaurants and corner stores stocked with unhealthy choices, present challenges.
"It's about supply and demand, the structure of cities and historical zoning issues," he said. "A bigger question is: What is it about access to these restaurants that's triggering?"
The study found no increase in obesity risk based on the distance from home to grocery stores and sit-down restaurants. What appears to put youths at risk is how easily and quickly they can access junk food, Elbel said.
He said further research was needed to explore what happens when children pass fast-food outlets on the way to and from school.
There has been a lot of voluntary regulation, he said, with the food industry agreeing to clamp down on advertising to children. But, Elbel said, government bears some responsibility to regulate.
"Policy has been proposed that addresses the density of these kinds of restaurants," he said. "London had considered restricting fast food around schools. We already limit liquor stores around schools and churches."
Obesity rates for children have tripled since the 1970s, and experts say a drop of just a few percentage points could save thousands of children from diabetes, heart disease and other health problems.
According to a National Survey of Children's Health report released this month, obesity rates among youths ages 10 to 17 averaged 15.3% nationwide, with a childhood obesity rate of 25.4% in Mississippi.
Nationwide, black and Hispanic youths had obesity rates of 22.2% and 19% respectively, significantly higher than white (11.8%) or Asian (7.3%) youths.
But the root causes are confounding — how to tweeze out genetic predispositions from lifestyle choices and income — and this muddies what can be done about it.
It has not been all gloomy news for children's nutrition. According to the Robert Wood Johnson Foundation, over the past several years there has been a decline in obesity rates among some children.
More than 30 million children eat healthier school breakfasts, lunches and snacks thanks to the updated nutrition standards ushered in by the Healthy, Hunger-Free Kids Act of 2010. The obesity rate among children participating in the Special Supplemental Nutrition Program for Women, Infants and Children (WIC) declined from 15.9% in 2010 to 13.9% in 2016. Researchers from the Centers for Disease Control and Prevention cited recent healthy updates to the WIC food package as one possible driver of the decline in obesity rates.