TUESDAY, Dec. 9, 2025 (HealthDay News) -- Pediatric obesity rates increased from before to during the COVID-19 pandemic, according to a study published online Dec. 3 in Pediatrics.Sarah E. Messiah, Ph.D., M.P.H., from the University of Texas Southwestern Medical Center in Dallas, and colleagues conducted a serial cross-sectional analysis comparing National Health and Nutrition Examination Survey data from before (2017 to March 2020) and during (August 2021 to August 2023) the COVID-19 pandemic to examine changes in pediatric obesity prevalence. Ultraprocessed food (UPF) intake and physical activity (PA) patterns were assessed via 24-hour dietary recalls and self-report, respectively.The analysis included 4,756 and 2,501 participants in the prepandemic and pandemic periods, respectively. The researchers found that the prevalence of obesity was 21.2 and 22.6 percent prepandemic and during the pandemic, respectively. There was a decrease in the mean percentage of UPF intake from 66.0 to 62.7 percent. Youth with higher PA days had lower odds of class II and overall obesity before the pandemic (odds ratios, 0.86 and 0.91); the protective effect across class I and III obesity did not reach statistical significance. Meeting PA guidelines was also protective against overall obesity during the pandemic (odds ratio, 0.86). During the pandemic, there were no significant predictors of obesity by class, but protective nonsignificant effects of PA were seen."This was a substantial increase for pediatric obesity rates given the short time period," Messiah said in a statement. "It is important for pediatricians to be aware of these recent trends when assessing and counseling patients and their families."Abstract/Full Text (subscription or payment may be required).Sign up for our weekly HealthDay newsletter