Obesity often seems like an adult issue, and the numbers are alarming: an estimated 40% of U.S. adults meet the threshold for obesity, defined as a Body Mass Index of 30 or higher (BMI is a weight-to-height ratio).

An additional third are overweight, with a BMI over 25. That puts perhaps 70 percent of American adults at risk for weight-related health problems, which can include heart disease, hypertension, Type 2 diabetes, chronic kidney and liver diseases, reproductive issues, musculoskeletal issues and some forms of cancer. 

But the trend is troubling among children, too. Prevalence of obesity is nearing 20% of U.S. children ages 2 to 19, affecting about 14.7 million children and adolescents, according to the Centers for Disease Control and Prevention. It disproportionately affects Hispanic and Black children. Studies have indicated that 70 to 80% of adolescents with overweight or obesity will be obese as adults. 

The College of Public Health and its Center for Obesity Research and Education (CORE) have made childhood obesity a major area of research. CORE researchers from across the college are working to unravel the complex web of physical and environmental factors that can influence childhood weight gain. 

“Children are situated within families, school systems, and communities,” says Gabriella Maria McLoughlin, assistant professor in the Department of Kinesiology and a CORE faculty affiliate. “These complex socioecological layers have a profound impact on their health and must be treated with equal importance.” 

Health challenges linked to obesity can be compounded by negative psychosocial effects when children experience stigma. 

“We know that stigma starts early and colors every aspect of children’s lives,” says Jennifer Fisher, professor in the Department of Social and Behavioral Sciences and director of CORE’s Family Eating Laboratory. “The research tells us that children with obesity experience stigma from teachers, from their peers, and even when they walk into a doctor’s office.” Consequences of that stigma can include depression, anxiety, disordered eating, and avoidance of physical activity. In adulthood, weight bias can lead to discrimination in employment and healthcare and in interpersonal relationships.

Treatments for obesity continue to improve and can be valuable options for adults. In children, early prevention can make a difference. The goal is to develop real-world interventions and strategies to guide caregivers and public policy makers in supporting children so they can form healthy lifelong habits.

Supporting caregivers of young children

Development of health-promoting behaviors should start early, including when children begin eating solid foods and deciding what they like. Fisher co-chaired a national panel of experts that in late 2021 published healthy eating guidelines for children ages 2 to 8. Aimed at parents and pediatricians, the guide is “a state-of-the-art toolkit of science-backed resources to support caregivers in feeding young children,” says Fisher.

“The U.S. Dietary Guidelines tell us what to eat to be healthy, but these new guidelines go beyond that, pulling together the science on what we know about the hows of feeding young children,” Fisher explains.

One of the most effective strategies for helping children between 2 and 8 learn to eat healthy foods is creating repeated opportunities for children to try them. The process takes time and differs for each child—some may need to try something up to 15 times before liking new foods, the report states. But Fisher notes, “The real keys to success are patience and making the process a positive one for the child. Many young children are wary of trying new foods. Sitting down and enjoying foods with your child, praising your child for trying a new food, or even taking smaller steps like smelling it—these are all ways to help children be willing to explore.”

Pressuring children to eat certain things doesn’t work well, the report says. “In the moment, it feels like it works—because children will comply and eat—but the research shows that it tends to backfire in the long term, by cultivating dislikes,” Fisher explains.

Giving children a role in their own eating choices can be more effective. That may be offering guided choices (a choice of strawberries or grapes, for example) or getting children involved in meal selection, preparation, and cooking. The full report is available online at HealthyEatingResearch.org.

Developing healthier snacking habits

Beyond age 8 and into their teen years, children are on their own more, often making multiple between-meals food choices every day. Snacking contributes significant calories to the overall diet, but often parents and kids aren’t closely watching what is eaten as snacks. Gina Tripicchio, assistant professor in the Department of Social and Behavioral Sciences and a CORE researcher, has carved out a specialty exploring snacking’s association with weight status and its underappreciated importance as an eating behavior.

“Despite how common snacking has become, there’s not a lot of literature that uses rigorous methodology to look at how it affects overall intake, weight, or diet quality,” says Tripicchio. “We’re interested in developmental differences in snacking. For example, adolescents have more autonomy, so their snacking behaviors differ from younger children.”

Working with Fisher, she is seeking a clearer picture of how teenagers should snack to stay healthy and avoid weight-related issues. Like much research on diet, the findings aren’t always clear cut.

“In teens, we found that eating snacks was associated with better diet quality, but it was also associated with obesity and high intakes of added sugar, saturated fat, and sodium,” she says. “Snack size is another important consideration. The larger the snack, meaning more calories, the worse it is for diet quality and weight.” That means children and teens should ideally aim to eat smaller, nutrient dense snacks, like fruit, and avoid large portions of snacks high in added sugar, fat, and sodium.

Timing is relevant too. “We did an analysis looking at late-night snacking and found that almost 40% of teens are consuming snacks between 9 p.m. and midnight,” Tripicchio says. During that brief time-period, they may be meeting their daily recommendations of added sugar.

Tripicchio recently received a fiveyear grant from the National Heart, Lung, and Blood Institute to examine added sugar in teens. Her work could lead to a set of age-specific guidelines as well as a mobile phone-based intervention that could help teens reduce their added sugar intake.

“We want to gain a better understanding of how, what, when, and why teens make food choices so we can design programs that are effective for this age group,” Tripicchio says. “If we can positively impact diet during the teen years, this has implications for health through adulthood.”

Timing of sleep and other behaviors

Chantelle Hart, professor in the Department of Social and Behavioral Sciences and researcher at CORE, has been conducting research on behavioral targets for obesity prevention and treatment. Recently she embarked on a study, funded by the National Institute of Diabetes and Digestive and Kidney Diseases, to explore how the timing and consistency of children’s sleep, eating, and physical activity may affect weight regulation over time.

“We know it’s important how much sleep kids get, how many calories they’re taking in, how physically active they are. What we’re trying to understand better is whether the timing and consistency of those behaviors might also be important for weight regulation,” says Hart.

Studies with adults have shown there are benefits when sleep and eating behaviors are aligned with circadian rhythms, the biological cycle that evolved to make people alert or sleepy during a 24-hour period. “When the timing of sleep and the timing and distribution of eating are aligned with someone’s underlying circadian rhythm—meaning you’re awake and eating when your biology says you should be awake and eating—that seems to be associated with better weight regulation,” Hart explains.

Hart’s team plans to closely track activities of 176 children from diverse socioeconomic backgrounds. The focus will be on early school-aged children ages 5 to 8 years. Assessments over the course of 16 months will measure multiple factors including the timing and consistency of children’s sleep, the timing of their physical and sedentary activity, their eating, and timing of the circadian clock. The researchers will record changes in children’s height, weight, and percent body fat and examine associations over time. Measures also will be made of participants’ home and neighborhood environments.

“We’re hypothesizing that children who live in under-resourced communities may be at increased risk for disruptions to their behavioral rhythms,” Hart says. “If, for example, you’re in a neighborhood that might have higher rates of crime, it may influence your ability to get a good night’s sleep or go outside and play regularly.”

Food environments matter

There’s increased recognition of the role that environment plays in childhood weight regulation. Human genetics haven’t changed in 50 years, but the way we live has, affecting our bodies in new ways. Thanks to technology, children and adults may be more sedentary. The dramatic rise in U.S. obesity prevalence over the past five decades closely parallels the explosive growth of the fast food industry and the soft drinks business (though sugary beverage sales have tapered in recent years). Recent research demonstrates that children and teens view multiple fast food TV ads daily and that ads disproportionately target Black and Latino youth. Fast-food portion sizes have also ballooned.

In less affluent areas, there may be an abundance of fast food restaurants offering calorie-dense foods, as opposed to full-service restaurants and grocery stores. The same neighborhoods with poor nutritional options may expose children to adverse experiences that also have been linked to obesity.

“Neighborhood influences obesity risk, whether that’s access to healthy food, access to green space, air pollution, poverty, or walkability,” says Krista Schroeder, assistant professor of nursing. She is in the middle of a five-year study disentangling the associations among obesity, neighborhood factors, and adverse childhood experiences (ACEs), traumatic events such as violence, abuse, or neglect.

“Part of the reason ACEs are associated with obesity is because the chronic or severe stress that results from ACEs can alter eating behavior through changing the way your hunger hormones regulate appetite or changing the way you may use food,” Schroeder says. “That might be amplified if you live in a neighborhood where it’s easy to buy unhealthy foods or there are many unhealthy food advertisements.”

With funding from the National Institute of Child Health and Human development, Schroeder is analyzing an array of geographical data, including Environmental Protection Agency information on air pollution, crime statistics from the city of Philadelphia, and data on neighborhood transportation access, green space, supermarket, and fast-food density. Using mapping and spatial analysis, her team hopes to identify population-level health associations.

Brittany Schuler, assistant professor in the School of Social Work, is examining ACEs and obesity at a more individual level. In a multiyear study funded by the National Institute on Minority Health and Health Disparities, Schuler is conducting focus group conversations in the Philadelphia community with parents and caregivers, gathering information about family experiences with adversity when children are very young, before age 3. This will be assessed along with information about the quality of children’s diets and trends in their BMI as they move into mid- and late-childhood (ages 5 to 9).

The research may tease out how traditionally defined forms of adversity (harmful events like maltreatment and exposure to violence) differ from or worsen the effects of situations like deprivation, poverty, or food insecurity. Understanding more about these dimensions can inform future pediatric obesity interventions for those disproportionately exposed to adverse environments, Schuler said.

“We could start plugging into prevention interventions, to sort of nip this in the bud before risks of excess weight and chronic illness set in,” she says.

Helping schools implement a safety net

Translating research into action, such as community programs or evidence-based guidelines for caregivers, is a goal of the CORE research faculty. McLoughlin is launching a project to help public schools serving low-income communities achieve the optimal impact of universal school meal programs, which are designed as a safety net to mitigate food insecurity.

Longitudinal studies have shown that free school meal programs that meet federal requirements for nutrition can be a mitigating factor for obesity, she says. But the programs work better in some schools than others. McLoughlin is working with the nonprofit Urban School Food Alliance to survey school meal administrators across the country, with a plan to create implementation and measurement tools that school systems and researchers can use. She also is partnering with the School District of Philadelphia to focus on implementation solutions for school meals and addressing equity in nutrition security.

“We’re trying to show schools how to make smart decisions, so they can show that universal school meals are actually worth the money. This is about seeing school meals as an investment, not a cost burden,” she says.

Providing these kinds of real-world tools for children, parents and policymakers is more important than ever, Temple’s CORE researchers believe.

“The food environment, as well as our eating behavior, has changed pretty dramatically in the recent decades since obesity has emerged as a major threat to public health,” Fisher says. “One of the realities for parents who are raising children in the current ‘obesogenic’ environment is the need to go out of your way and be quite purposeful in helping children cultivate healthy eating habits. Because the current environment certainly doesn’t encourage it.”