Rates of childhood obesity have increased, study finds

Despite national school and community-based efforts to promote healthy behaviors at a young age, childhood obesity is becoming more common in the United States, a recent study found.

The research, published Tuesday in the journal Pediatrics, followed two nationally representative groups of children from kindergarten to fifth grade – around ages 6 to 11. The first group was studied from 1998 to 2004, and the second group was studied from 2010 to 2016.

The difference between the two groups was striking: Around 16.2% of children who did not have weight issues when they entered kindergarten in 2010 were obese by the end of fifth grade, compared with 15.5% of participants in the same BMI category who started in 1998. Additionally, children studied in 2010 became obese at younger ages than their predecessors in the 1998 group.

In both groups, children who were overweight during their preschool years had a significantly higher risk of obesity than their peers who were not, researchers found.

“Once you get on that train towards elevated weight gain, it’s really hard to turn it around, so prevention of overweight and obesity really early on are so important,” said Solveig Argeseanu Cunningham, first author of the study and associate professor of global health and epidemiology at Emory University in Atlanta.

Obesity occurs when a person has excessive fat accumulation that presents a health risk, according to the World Health Organization. Adults who have a body mass index (BMI) – a calculation based on one’s height and weight – over 30 are considered obese. Childhood obesity is measured not by exact BMI, but by comparison to other children of the same age and sex. Those who are in the 95th percentile of BMI for their age and sex are considered obese, according to the Centers for Disease Control and Prevention.

Obesity is a major underlying risk factor for many illnesses, including type 2 diabetes, cardiovascular disease, certain cancers and severe cases of Covid-19, according to the Mayo Clinic.

“Without intervention, we will continue to see increasing prevalence and severity of obesity for children at a younger age, which has really negative consequences down the line, not just for these children, but also for their future offspring,” said Dr. Jennifer Woo Baidal, director of the Pediatric Obesity Initiative at Columbia University in New York City. She was not involved in the study.

Childhood obesity risk factors

Since the study looked at children prior to the spread of Covid-19, it doesn’t account for the pandemic’s effects on childhood obesity. However, some doctors suspect that rates have continued to increase, especially among children of color.

Children of color, particularly Black and Hispanic children, were at the greatest risk of developing childhood obesity, according to the study. Non-Hispanic Black children who were not overweight when they entered kindergarten in 2010 were 29% more likely to develop obesity by fifth grade than their counterparts who started in 1998.

Socioeconomic status was not a strong predictor of childhood obesity, according to the study.

“That was unexpected because we’ve generally seen kids from wealthier households be more protected from a lot of health issues, especially obesity,” Cunningham said. “This really highlighted for me that obesity affects everybody across socioeconomic status.”

Since the study only followed children until fifth grade, researchers are uncertain how socioeconomic status and race affected rates of obesity once the participants entered sixth grade and beyond. However, based on previous studies on adult obesity, it is likely that children of lower socioeconomic status would have greater rates of adult obesity, said Dr. Venkat Narayan, a senior author of the study and the executive director of the Global Diabetes Research Center at Emory.

“Lack of access to healthy foods, lack of access to physical activity, higher unemployment, all of those factors can collaborate to increase the risk of diseases like obesity, diabetes, cardiovascular disease,” Narayan said.

An issue of public health

Since 2010, numerous public health efforts have been implemented to reduce rates of childhood obesity, including Michelle Obama’s Let’s Move campaign and the Healthy, Hunger-Free Kids Act. Despite these efforts, rates of childhood obesity have increased, a sign that these actions may not be as beneficial as people assume, Cunningham said.

Experts believe that lowering rates of childhood obesity may come down to public policy, such as improving school nutrition packages and expanding the Supplemental Nutrition Assistance Program (SNAP).

“Those types of policy changes, there’s some evidence that they reduce food insecurity, improve nutrition, and can improve child weight outcomes together in an equitable way,” Baidal said.

However, since socioeconomic status was not a major predictor of childhood obesity, policy changes may not be enough on their own, Narayan said.

More organized research is needed to find the factors leading to increased rates and earlier onsets of childhood obesity, as well as finding strategies to effectively prevent obesity from becoming more “severe,” he added.

“Other countries keep large registries and databases, where they can have this timely surveillance of what is happening over time with individuals,” Baidal said. “It’s just another sign of the lack of investment in child health and (obesity) prevention in the United States.”

Home interventions for childhood obesity

Traditional methods of weight management, such as strict diets, don’t always work and can sometimes be unhealthy, Cunningham added.

There is no single recommended prevention or intervention method for childhood obesity. The most useful thing parents and caregivers can do is speak to their child’s pediatrician, Baidal said.

Teaching healthy habits – including physical activity, nutrition, good sleep and reducing stress – is another way parents and caregivers can work toward decreasing childhood obesity, she added.

“What the literature is showing is that the most effective treatment involves family based behavioral treatments, where we’re teaching families about behavioral strategies to help change the home environment,” said Dr. Kyung Rhee, professor of pediatrics at UC San Diego, who was not involved in the study.

It can be helpful for parents and caregivers to emphasize the importance of these habits for the whole family, so that the child does not feel shame or blame for their weight.

While obesity can be a predictor of health issues, emphasizing weight loss is not always a helpful solution, said Rhee, who works with patients who have eating disorders and those with childhood obesity.

“Reframe the whole thing in terms of healthier lifestyles and healthier environments,” Narayan said. “It’s better to talk about eating healthy, adequate physical activity for children, adequate play environments, safer play environments, particularly in poorer socioeconomic neighborhoods.”