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This article is from the In-Depth Report New Insights into Obesity

Hidden Drivers of Childhood Obesity Operate Behind the Scenes

New research reveals that the obesity epidemic in children has more complex causes than just diet and exercise



Tobyotter, Flickr

Anxiety around children's eating habits often peaks during sweets-laden holidays like Halloween, but the factors that contribute to excess weight in kids extend well beyond special occasions. Most children who are obese—now 17 percent in the U.S.—will carry that extra heft into adulthood, along with the long-term health consequences. Scientists project that today's generation of children will live shorter lives than their parents and have higher rates of heart disease, diabetes and atherosclerosis. Despite diverse efforts—from First Lady Michelle Obama's Let's Move campaign to the U.S. Department of Agriculture's MyPlate nutrition guidance changes—the number of overweight and obese children does not seem to be dropping, which has sent scientists searching for other drivers of the childhood obesity epidemic.

One group at the University of Illinois at Urbana–Champaign is enlisting experts from fields as wide-ranging as genetics and communications to try to untangle the intricate web of forces that yields a profusion of pudgy kids. "It's cellular makeup, it's child behaviors and child attributes, it's family behaviors within communities and environments within state and national level policies," says Kristen Harrison, founder of the university's Synergistic Theory and Research on Obesity and Nutrition Group (STRONG) Kids project. "It's incredibly complex." Factors such as heredity, access to exercise, parental food habits and cultural differences in portion sizes are all known to contribute to childhood obesity.

And these factors do not exist in isolation. "What we don't really know yet is how those factors interact with each other," Harrison says. And recently researchers at STRONG and elsewhere have started uncovering additional, surprising drivers of obesity, such as sleep schedules and the frequency of family meals.

Visualization is courtesy of TheVisualMD.com

More to diet and exercise
Getting kids to eat healthfully and get more exercise might sound simple, but the long list of genetic, cultural and environmental factors that lead children to these behaviors are complicated and interconnected, and scientists have just started to understand them in the past few years.

Fresh fruits and vegetables, for example, are not always accessible. Some communities have plenty of grocery stores that stock fresh, healthy foods, whereas other neighborhoods have only fast-food chains and corner convenience stores, making it difficult to get enough healthful items. "A family may be really motivated, but if it takes two bus rides to get to a store that carries fresh produce, it's hard," Harrison says. Outside the family sphere, children are also often confronted with a wide variety of pound-packing options in vending machines and even in school lunches.

Budget cuts at schools have also cut back on sports and physical education programs, reducing the amount of exercise kids get during school hours. And a lack outdoor play spaces like parks and woods can also hamper parents' good intentions. "Parents who live in neighborhoods that aren't safe, aren't going to send their kids to play outside," Harrison says. And an indoor lifestyle makes it difficult for children to get enough exercise to keep their weight down—or lose weight that they currently have.

The researchers are also quick to point out that all the blame cannot fall solely on parents either. "Often people say, 'Well parents, just stop feeding your kids so much,'" Harrison says. "There's an attitude that people are stupid, they're greedy, they don't care. And that couldn't be further than the truth." When parents in low-income communities are asked about nutrition, they know the right answers, he says. They know that their kids should be eating more fruits and vegetables, and less fast food. "So there's something way beyond just education."

Television watching, for example, turns out to be a better predictor of bad eating habits than does parental weight, race and income, and a child's gender and ethnicity—together—according to a study by Harrison and her team. This is probably prompted by child-targeted food marketing, combined with a sedentary lifestyle and snacking while watching. One study published in the Archives of Pediatrics & Adolescent Medicine in 2006 estimated that for every hour of daily television, kids consumed an additional 167 calories.

Visualization is courtesy of TheVisualMD.com

Deeper drivers
Parents, schools and even family doctors might be pardoned if they have neglected to consider some of the newly described factors that might be behind childhood obesity. In one study unconnected with the STRONG Kids Project, researchers in Australia set out to study how sleep might affect weight. They found that, contrary to their expectations, it was not the amount of sleep that mattered, it was timing, says Carol Maher, a postdoctoral research fellow at the University of South Australia and lead researcher on the study. Children who went to bed early and got up early were far healthier than those who went to bed late and got up late, even though the two groups got the same amount of sleep.

It could be that those who go to sleep later spend more time watching television. Mornings tend to be better for exercise, whereas evenings are prime computer and television times—which means less exercise, more snacking, and more exposure to food marketing. But, Maher points out, it could also mean that kids who are more physically active during the day tend to get tired earlier, and go to bed earlier.

How often kids eat with their families also might impact childhood obesity rates—one group found that every meal not eaten with the family each week predicted an 8 percent increase in the likelihood that a child would be overweight. And health benefits of home-cooked meals might not be the only reason for this correlation, Harrison says. The simple act of a reliable family meal could also be adding psychological stability. Kids who feel like they have a support system and can manage their emotions tend to be healthier overall. Family mealtimes often provide parents a place to spot behavioral warning signs for depression or other unhealthy stressors.

Harrison hopes data from the STRONG Kids program will help policymakers examine the blind spots in current strategies. Because the drivers of childhood obesity are complex, solutions will have to be so, too, she says. Instead of tackling one factor, "they'd be double-barreled and triple-barreled policies," she says. For example, she said, policies that affect schools could address several of the causes of childhood obesity, such as access to vending machines, physical activity requirements, and even teaching students healthier habits. "If you attack a bunch of the influences at once," Harrison says, "you're going to get a much more powerful effect."

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