“Significant weight gain occurred during the covid-19 pandemic among youths in Kaiser Permanente Southern California, especially among the youngest children,” the study concluded. “These findings, if generalizable to the U.S., suggest an increase in pediatric obesity due to the pandemic.”
The study, which used Kaiser Permanente Southern California electronic health record data from nearly 200,000 children ages 5 to 17 to track weight gain during the pandemic, is considered one of the largest of its kind, experts said.
What’s alarming about this study is “how large the change was in a very short period of time,” said Barry Popkin, an obesity researcher at the School of Public Health at the University of North Carolina at Chapel Hill. He added that about 15 other studies in both high- and low-income countries reflect a similar trend, when it comes to pandemic-spurred obesity in children.
The JAMA report pointed to an increase in obesity among the youngest age group during the pandemic year that was higher than the increase in this group over the past 20 years. Among 12- to 15-year-olds, the study showed a rise in obesity levels during the pandemic that matched the increase that had occurred over the past 20 years. And among 16- to 17-year-olds, the pandemic year weight gain was about half the rate of increase in obesity compared to what teenagers that age had shown over the past 20 years.
“Purchasing patterns and activity patterns both went in the wrong direction,” Popkin said. “Kids in school had to be in front of computers, and there were lockdowns that kept people inside. But the bigger increase was the increased purchase of ready-to-eat junk food, foods high in calories, saturated fat and added sugars. The sale of these went up more than any other category.”
“They tend to gain weight at an accelerated rate, then during the school year their body mass index goes down, but not as much, so over time kids are getting more and more overweight and obese,” Ritchie said.
Regular summer weight gain among students is attributed to missing recess, P.E. and school sports, as well as not getting exercise associated with traveling to and from school, Ritchie said. It is also because studies show that school meals are, on average, healthier than what children bring from home. Also, kids in school have access to breakfast and lunch; at home during the summer there is frequently unfettered access to food all day long.
Ritchie said that companies selling junk food have had more access during the pandemic to market directly to children who spent more time on screens.
“What this has taught us is that our food environment is way out of line with what we need. Food companies are geared to getting us to eat as many calories as possible,” Ritchie said. “And we are geared toward eating when food is available.”
Marion Nestle, an author and nutrition professor at New York University, said that children’s pandemic weight gain may also be a signal of parental fatigue.
“What I’m hearing from parents is that they just don’t have the bandwidth to worry about what their kids are eating. It’s too much on top of everything else,” she said. “Nobody is weighing their kids. All they want is for their kids to not be miserable. But we’re not just talking about cosmetics here, we’re talking about the risk of Type 2 diabetes.”
The study followed young people over time to compare weight gain and body mass index before the pandemic with that during the pandemic, adjusting for age-related growth.
Deborah Young, one of the study authors and director of the Division of Behavioral Research for the Department of Research & Evaluation, said that the Kaiser Permanente health-care system insures about 25 percent of the Southern California market. She said that although the data omitted household income and education levels, it broadly represented the Southern California population overall.
For Young, the message for parents, school districts and policymakers is that if these situations happen again, “we need to have policies and interventions in place that encourage kids to be active, that keep the parks open and that encourage the intake of appropriate and healthful foods,” she said.
An earlier version of this story reported the childhood obesity study had been published in the Journal of the American Medical Association's network of journals. The study was published in the Journal of the American Medical Association (JAMA).