A new study by leading U.S. researchers shows a sharp rise in ultra-high obesity among children over the past decade and a half. Using nationally representative health data, the study in JAMA Network Open found that the share of children in the most extreme obesity categories more than tripled from 2008 to 2023. With about 73 million Americans under 18, this translates to roughly 825,000 children now in the ultra-high BMI range. Ultra-high obesity is defined as BMI levels well above the 95th percentile, reaching Class 4 or Class 5 levels. The trend raises critical questions for Thailand, where childhood overweight and obesity are also rising.
A UC San Diego–led team focused specifically on Class 4 and Class 5 obesity and their health consequences in youth. The findings show that children in these categories are developing health problems once seen mainly in adults, including fatty liver disease, type 2 diabetes, and metabolic syndrome, even before finishing high school. A senior pediatric specialist notes that these young people are facing adult-type complications years earlier, potentially shortening life expectancy and increasing burdens on families, clinics, and the health system.
Researchers analyzed data from national health surveys spanning 2008 to 2023. They found a strong link between BMI severity and the risk of serious health issues: children with extremely severe obesity are much more likely to have fatty liver and insulin resistance, and to display advanced liver changes compared with peers with milder obesity.
Experts point to multiple contributing factors, including diets high in ultra-processed foods and sugary drinks, reduced physical activity, pandemic-era lifestyle shifts, and genetic predispositions. The study’s lead author emphasizes that weight gain is shaped by the environment as much as personal choice—a perspective that resonates in Thailand, where rapid urbanization, changing diets, and pandemic disruptions have contributed to rising childhood overweight, particularly in Bangkok and other urban centers. Thai health data show a worrying upward trend in pediatric overweight that echoes global concerns.
The study calls for refined definitions to better capture health risks facing these children. Current classifications label severe obesity at 140 percent or more above the 95th percentile, but the authors advocate new categories and tailored interventions. Recognizing the distinct vulnerabilities of Class 4 and Class 5 obesity could improve diagnosis, treatment, and outcomes.
Thailand’s health landscape mirrors these global challenges. National health surveys indicate rising obesity among children aged 6–14, with rates climbing in the last decade as sedentary habits and high-calorie foods proliferate. Like their global peers, Thai children with higher obesity levels face increased risks of diabetes, hypertension, and mental health distress. Local clinicians are documenting these trends in major hospitals, underscoring the need for urgent action.
Policy and practice implications include clearer food labeling, healthier school meal standards, and tighter controls on junk food marketing to youth. Expanding access to safe spaces for physical activity and evidence-based interventions is equally important. While new weight-loss medications show promise for substantial BMI reductions, these treatments remain expensive and inaccessible for many families in lower-income settings. Experts argue that children with Class 4 and Class 5 obesity should be prioritized for access to effective therapies and that pediatric-focused clinical trials are essential.
In Thailand, universal health coverage aims to improve access to medicines, but access to novel anti-obesity drugs is constrained by cost and regulation. Stigma around childhood obesity and limited school-based programs outside international schools further challenge efforts. Public health campaigns promoting healthy eating and active living have gained traction, but gaps remain—especially for urban teens and lower-income families who lack safe spaces for exercise.
Historically, Thai diets emphasized vegetables and fish, helping guard against chronic disease. As urban migration accelerates and Western fast foods become more common, Bangkok and other cities face new risks. Addressing these trends requires coordinated action across sectors—education, healthcare, urban planning, and family support—along with targeted programs for schools to promote physical activity and nutrition.
Experts warn that reversing extreme childhood obesity will require a multi-sector approach, engaging healthcare workers, educators, community leaders, and policymakers. Early screening and family-centered lifestyle interventions, along with appropriate medical treatments when needed, could reduce long-term health burdens and healthcare costs.
For Thai readers, the core message is clear: childhood obesity is a systemic issue shaped by the food environment, school culture, urban living, and public policy. If families have concerns about a child’s growth trajectory, they should consult a pediatrician and explore community exercise resources and health education programs. Policymakers are urged to prioritize early prevention and equitable access to effective treatments as part of Thailand’s broader public health agenda.
Data and guidance can be found in global health resources and Thai public health data, underscoring the shared importance of protecting children’s health today to secure a healthier tomorrow.