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How can we halt the health hazard of childhood obesity? ����ɫ��ҹ researchers weigh in on their latest findings. 

By Michael Blanding

The stock market fluctuates, hemlines go up and down, but one thing reliably keeps getting higher: the weight of American children. Since the 1970s, the percentage of kids in the United States who are classified as either overweight or obese has more than doubled. According to the latest figures from the Centers for Disease Control, now more than 35 percent of children and teens are either overweight (with a body mass index or BMI over 25) or obese (with a BMI over 30)—for the first time crossing the threshold of one in three children with a weight problem.

Since the 1970s, the percentage of kids in the United States who are classified as either overweight or obese has more than doubled.

By now, the dangers of those extra pounds are well-known—obese children are more likely to suffer from heart disease, type 2 diabetes and breathing problems such as asthma, among other ailments. And they also are likely to experience social and psychological consequences, including a greater likelihood of being bullied and having low self-esteem. The threats to children’s weight have never been more dire, with the ubiquitous presence of high-calorie processed foods and the temptations of technologies that encourage kids to spend more time sitting and staring at screens. 

Despite those challenges, researchers at ����ɫ��ҹ continue to make inroads in helping us understand obesity and combat it in our children. We talked to four scientists who are researching different aspects of the epidemic about what they have discovered—and how we might apply it to help keep our kids healthy.

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DOES YOUR BRAIN DECIDE WHO’S AT RISK FOR OBESITY?

Your children may be hardwired to be active or sedentary, but you can help them establish healthy habits at an early age. 

It’s long been known there’s a genetic component to obesity. Some people seem to eat whatever they want and not gain weight, while others struggle to shed pounds. Research by associate professor of biological sciences Colleen Novak, PhD, provides one reason why: it’s all in our brains. 

Novak has focused her research on rats—examining why some rats tend to be highly active, always flitting around their cages, while others tend to be more sedentary. “I started looking at the brains of these rats, focusing on what made them high or low activity,” she says. 

In particular, she has honed in on the melanocortin system, a network of neurons in the brain that has been tied to weight regulation. Rats with higher activity, she found, have more receptors in that system for certain peptides—tiny strings of amino acids that tell the brain to burn more energy, even when the body is only moderately active. 

Those peptides, or some like them, could be key to explaining differences in humans, as well. Before coming to ����ɫ��ҹ, Novak studied at the Mayo Clinic with Jim Levine, a world-renowned obesity expert who has coined the term Non-Energy Activity Thermogenesis, or NEAT, to refer to the amount of energy we burn in daily living. Like people with high NEAT, rats with high NEAT tend to move around more during the day—and their muscles literally burn hotter when they do, consuming more calories for the same amount of activity.

Hypothesis: The brain sends signals to the rest of our body based on our level of NEAT, telling it to take in more energy by eating or expend more energy through activity. “When you have enough calories and you don’t need to eat, these peptides tell you to feel free to be active,” Novak says. “Their counterparts do the opposite; they will make you eat more and suppress your calorie burn.” 

In her research, Novak has been able to inject sedentary rats with a drug to activate more receptors in the brain, leading them to become more active and lose weight. “The efficiency of their muscle cells actually changes, and they will burn more calories,” she says.

Possible human application: One eventual outcome of Novak’s research may be the creation of a similar drug for humans, helping them increase activity and burn more calories with less effort. While that may seem like a magic bullet for weight loss, Novak hastens to explain that such a drug might only result in the loss of a pound or two at most. 

The more immediate benefit of her research may be in identifying the genes in humans that result in higher or lower NEAT. Since young children are more active than adults in general, it can be difficult to identify who might be inclined to be sedentary later in life and, therefore, more at-risk for gaining weight. “Parents aren’t always reliable in detecting weight problems in their kids,” says Novak. “We need to get the message to them if we want to have an impact.”

What to do right now: Until we can identify which children are more genetically inclined for low NEAT, parents can help jumpstart healthy habits that could override a body’s natural tendency to gain weight. For example, they can encourage more exercise, restrict access to high-calorie snacks and ensure that kids develop healthy eating habits. They can also make an extra effort to determine what physical activities their children like best, so they can get used to exercising on a regular basis. “If children like doing something, they are more likely to continue doing it long term,” Novak says. 

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HELP REDUCE AND MANAGE STRESS

Stressful situations can lead to obesity, but they don’t have to.

Many of us know what it’s like to overeat when we’re under stress. But for low-income children, chronic stress can lead to chronic overeating.

Amy Sato, PhD, assistant professor of psychological sciences and director of the at ����ɫ��ҹ, has worked with teenagers from low-income backgrounds who live in areas where it’s not safe to go outside, so physical activity is difficult. Others experience food insecurity as a result of their parents’ financial stress. “Not always knowing you are going to have food around can cause you to overeat in anticipation,” Sato says. 

Since coming to ����ɫ��ҹ, she has researched how those stressors can lead to obesity, and how we can intervene to stop the cycle. 

Here are some things you can do to reduce your child’s stress and encourage a healthy weight—whatever your family income.

Show don't tell. Sato made a surprising discovery when, as a postdoctoral researcher at Brown from 2009 to 2011, she studied a group of teenagers in a 16-week weight loss program that included dietary change, physical exercise and cognitive behavioral techniques. 

After teens were weighed at the end of the program, the only independent predictor of whether they lost weight was whether their parents lost weight, too. It was even more surprising, says Sato, since “the parents weren’t targeted at all.”

Any talk of weight loss by parents can be interpreted by teens as criticism, adding to their stress, she says. However, when parents also make an effort to lose weight, they send a powerful message—without words.

Reduce temptation. One of the most effective ways to get kids to lose weight is to reduce access to high-calorie processed foods for everyone in the family. “By getting the Oreos and Doritos out of the house,” Sato says, “you are changing the environment for the kids.” 

Manage stress levels. In studies with adults, overeating has been associated with higher levels of cortisol, a hormone the body releases in response to stress. Stress may be a factor for children and teenagers who struggle with emotional eating, too. 

In an ongoing study funded through a $150,000 grant from the National Institutes of Health, Sato exposes low-income teens to stressful situations, such as public speaking in front of a group, and monitors their cortisol levels and the amount they eat when given access to food in order to gauge the correlation between physiological stress reactivity and eating. She also has them report on the stress they experience outside the lab, as well as the eating and exercise habits of their families. Over time, Sato hopes that this research will be helpful in exploring interventions that can reverse harmful patterns. 

Be mindful. One possible solution is teaching teenagers mindfulness meditation as a way to reduce the cortisol response and perception of stress. While such techniques may not dispel the stressors in these teens’ lives, Sato says, they could give teens more self-control to help manage stress and resist the temptation to overeat in response. “We all know the feeling when we are 80 percent full, but still feel somewhat hungry,” Sato says. “Mindfulness can help someone accept that discomfort in order to achieve a higher goal.”

Watch transitions. In another study that Sato conducted on the topic of stress, she found the transition to college—and the disruption associated it with it—can be a particularly trying time for teens, even if they haven’t struggled with their weight before. Examining 97 ����ɫ��ҹ first-year students, she found no change during the transition to college for those with the highest BMIs. However, for those who weren’t already overweight or obese, greater feelings of stress contributed to more emotional eating and weight gain. 

Those who had better coping mechanisms—for example, the support of family or friends and the ability to talk about their problems—experienced less emotional eating. Resources such as family support and therapy can help during this time of transition. 

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TURN OFF THE TUBE

Limit television viewing at an early age to help your child combat obesity now—and as an adult.

One of the biggest battles parents and doctors face in combatting childhood obesity happens right in our living rooms—in front of the television. For years, studies have associated watching greater amounts of television with a higher risk for being overweight or obese, the so-called couch potato effect. New research by Chance York, PhD, assistant professor of mass communication, has found that the threat caused by the tube is even greater and longer lasting than we realized—and that the benefits of cutting down on screen time can be even more effective in combatting obesity.

York’s research focuses on patterns of media usage over time, not just on a single snapshot. Recently, he used one of the longest running studies of human behavior to see how early exposure to television affects a person’s media usage and beliefs over time. Begun at the University of Michigan in 1968, the (PSID) is now on its fourth generation of study participants, allowing researchers to study not only the impact of behavior on an individual, but also on his or her children and grandchildren. 

“It is a cool dataset if you are looking at something like obesity because it has all of these height and weight details, and you can look at a person over a long period of time,” York says.

Cut down now, reap future benefits. For his recent study, York looked at how frequently children watched television in 1997, and then linked it to how frequently they watched television 14 years later, in 2011—and how that frequency of usage affected body mass index (BMI) over time. As with previous studies, he found an association between television and BMI; the more TV children watch, the more likely they were to be overweight. He also found that the more television children watch when they are younger, the more television they will watch as adults.

While having a high BMI as a child tends to lead to having a high BMI as an adult, York found an additional, independent effect on BMI of watching high amounts of television as an adult. In other words, watching a lot of television as a child causes a double whammy—leading to obesity as a kid, and then leading to more television watching, which can lead to obesity as an adult. 

“If you try and intervene when they’re kids and interrupt TV time, you could impact their BMI many, many years down the road,” York says. “You don’t have impact just over the next year or two, it could have an impact over the next few decades.” 

Exercise isn’t enough. The mechanism that leads television viewing to increase overweight and obesity isn’t completely understood, but York’s study found that it is independent of the amount of exercise a child gets. Some researchers have concluded that the extra pounds might come from extra snacking while watching TV, or exposure to advertisements for sugary snacks and cereal. Whatever the cause, it’s not enough for kids to watch 8 hours of TV and then go outside and run around to work off the calories—television seems to have its own unique way of packing on the pounds.

Leading by example. As alarming as his study is, however, York says it also offers an opportunity. Other research has shown that kids’ TV use is directly related to the example of their parents’ TV use. By breaking their own habit of switching on the tube, parents can potentially have an outsized influence on limiting their children’s television usage—as well as their tendency to become overweight. “Kids don’t always copy what their parents do,” York says. “But if parents are watching a lot of TV, then at the very least, their kids see it as acceptable behavior, and so they may watch as well.”

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GET KIDS MOVING

Social interactions and today’s technologies pose challenges for keeping children motivated to be active.

Jacob Barkley, PhD, says many of his ideas for research come from observing friends and family. That was the case a few years ago when the associate professor of exercise science and physiology was watching his then three-year-old playing in the backyard by himself. 

“He was moving slowly, not being very active,” Barkley says. Suddenly a friend came over, and the two started running around. “His level of activity increased dramatically.” And it inspired his father to explore further.

We asked Barkley, whose past research has focused on motivating children to make healthier choices, to tell us some practical implications of his recent research. 

Experiment: Intrigued by the effects of positive peer interaction on exercise, Barkley set up a controlled experiment in a gymnasium, filling it with mats, tunnels, cylinders, nerf balls, hoops and jump ropes in one area, and sedentary activities like coloring and puzzles in another. He then measured physical activity on an accelerometer for kids released into the space. When released on their own, he found that they gravitated towards the sedentary activities. But when they were released in pairs, they tended to be much more active. 

Implication: “Having another child there is inherently motivating and encourages more physical activity,” Barkley says. Since today’s style of parenting relies more on supervised playdates rather than just letting kids outside to play unsupervised, “It’s important that parents create opportunities for social interaction.” 

Experiment: In another study, Barkley introduced children to a computer simulated game of catch, in which each child was told he or she was playing with two other kids. In reality, the other two “players” were controlled by the computer, which randomized how much they threw the ball to the child. Children who were thrown the ball less often felt left out. When they were released into the same gym environment as in the previous experiment, they tended to do sedentary activities by themselves—causing them to be less physically active. 

Implication: “Often the kids who need more physical activity are the ones who tend to be targets of negative social interaction,” Barkley says. “Then that may further reduce the motivation to be physically active.” While schools have made headway in introducing anti-bullying programs, they may need to make an extra effort to include children who are overweight or obese.

Experiments: In his latest studies, Barkley collaborated with fellow associate professor of exercise science Andrew Lepp, PhD, to explore the effects of the newest threat to physical activity: cell phones. In a of ����ɫ��ҹ students, they found that high users of cell phones were sedentary for 90 to 100 minutes more than low or moderate users. And that trend may apply to younger children, as well.

In another study, Barkley, Lepp and former graduate assistant Mallory Kobak, PhD ’16, again filled a gym with active and sedentary choices, with one change: they added an iPad as an option. As a result, they found that when children were released into the gym on their own, they were drawn to the iPad and were much less active overall than when the iPad wasn’t available. 

Implication: The increasing prevalence of cell phones, tablets and other mobile devices presents a new danger in keeping children motivated to be active, Barkley concludes. 

“We need to start looking at the use of these devices as critically as we have looked at watching TV and playing video games,” he says. “It used to be that you could only be a couch potato at home. Now you can be a couch potato on a park bench surrounded by a wide variety of physical activity options.”

Michael Blanding is an investigative journalist based in Brookline, Massachusetts.

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