Campaigns to help children set aside junk food and soda appear to be paying off: The obesity rate for American teens has stopped rising, and may even be on the decline.
However, a recent study published in the journal PNAS finds that this trend is limited to families with more education and income. In 2002, obesity rates climbed at similar rates for all teens, but since has gone down for teens with a higher socioeconomic status, and gone up for low-income teens.
The findings reveal a growing class gap in childhood obesity, and might indicate that parents and teens have gotten the message about diet and exercise, but it's much easier for affluent families to act on it.
The calorie crusade
The study found that teens across the board are eating fewer calories. Between 1998 and 2010, children of parents with a college degree reduced their average calorie intake from 2,487 calories per day to 2,150 — or about the amount of calories in a medium serving of french fries. In the same period, less-advantaged teens, which had a lower calorie intake to begin with, also lowered their calories from an average of 2,271 calories per day to 2,105 —equivalent to a bottle of Coke.
Teens have been swapping out soda for lower-calorie drinks like Gatorade, or just plain water, says Julie Metos, Interim Chairperson of the Division of Nutrition at the University of Utah and registered dietician. While working with youths, she has also seen a trend in homes and schools away from foods laden with simple carbohydrates, like cookies and white bread, toward whole grains and vegetables.
Youth making better food choices is especially heartening, says registered dietician Hillary Chrastil, because food habits tend to be set at a young age. “Those early years is when food habits form, so by the time you are 13, 14, 15, if you are eating fast food and your school counts pizza as a vegetable, you’re not going to order a spinach salad,” Chrastil says. Lower calorie intake among teens should eventually lead to lower calorie intake for adults.
If calorie intake is down, the obstacle now — especially for low-income teens — is more exercise, says Metos.
“We have changed the model where kids get physical activity outside of school now, not in school,” Metos says, who points out that over the last couple decades, physical education programs have been compromised by a focus on standardized testing. “We forget that the physical body is not separate from the brain,” she says.
When youths aren't playing kickball or running laps at school, it can put those from poor families at a disadvantage because their parents are less likely to have the time and money to enroll them in private and community sports teams. Transportation, team dues and equipment costs are all obstacles.
A detailed survey of youths’ eating and exercise habits from Harvard University's Kennedy School of Government suggests that exercise explains the obesity gap for less-advantaged teens.
In 2011, 90.1 percent of teens living with parents with college degrees said they had exercised or played a sport for at least 20 minutes continuously in the last seven days, but only 80.4 percent of teens living with parents without high school diplomas said that they had done the same. Those numbers have gone up by 5 percent for advantaged children since 2003, but have stayed about the same for less-advantaged children.
The findings seem to indicate much more than education is needed to address the problem. “In low income families, often both parents are working, or are working two jobs,” says Kelli Horton, a registered dietician who did graduate research at a low-income school district in Los Angeles. “Time is a big limiting factor.”
The recession makes it harder to create changes, says Amy Bentley, associate professor in the department of nutrition, food studies and public health at New York University. "There is less money to buy healthy food, less time for a parent to be home to prepare healthier food, less money to participate in school sports," she says, noting that there is much more to the problem than just a culture of healthy eating. "Stress and strain propel people to eat comfort food," she says. "Poor people are stressed a lot."
One alternative to costly sports teams and clubs is just good, old-fashioned play, through access to recreational centers, parks and playgrounds. But it can be difficult for low-income families to have access to parks, green space and safe places to play.
Most volunteer after-school programs focus on homework, not physical activity, but that may start to change. The NFL 60 Minutes of Play program offers volunteer opportunities and ideas for after-school programs that feature jump rope relays and freeze tag. Metos notes that the last decade has seen an uptick in sports team enrollment, which could be due to obesity concerns, but could be influenced by other factors like looking good for college admissions. “Think not in terms of sports, but having fun with your friends,” Metos says.
Another solution, Chrastil says, might be policy. She wonders if teens got the message about sugar soda or if it just wasn’t available in schools anymore, replaced with Gatorade, water and juice. “Is that educational success, or policy success?” she asks, noting that her kindergartner only has physical education once a week at his school. “If physical activity is an issue, and we know policy changes can work, then they should be applied to exercise.”