BMI-perception discordance and school health communication profiles among US high school students: evidence from the 2023 Youth Risk Behavior Survey

Background: Body mass index (BMI) screening is commonly used in schools to identify students at risk of overweight or obesity, but BMI alone may not adequately guide counselling when students’ perceived weight differs from BMI-based status. Method: This cross-sectional secondary analysis used 2023 US Youth Risk Behavior Survey data from 17,814 students in grades 9–12. Survey-weighted estimates and logistic regression examined overweight or obesity, underestimation among students with overweight or obesity, and excessive concern among students without overweight or obesity. Results: Overall, 30.63% of students had overweight or obesity. Among students reporting perceived weight, 53.04% were concordant, 36.16% underestimated, and 10.80% overestimated their BMI-based status. Among students with overweight, 41.74% perceived themselves as about the right weight, whereas only 24.76% of students with obesity perceived themselves as very overweight. Among students without overweight or obesity, 13.16% reported excessive weight concern. Perceived slightly overweight (AOR 6.76, 95% CI 5.14–8.89), perceived very overweight (AOR 31.59, 95% CI 16.67–59.85), and weight-loss intention were key communication cues. These findings informed a non-diagnostic concordance-check framework for school health counselling. Conclusion: BMI screening should be complemented by brief assessment of perceived weight and weight-loss intention. Counselling should be private, non-stigmatizing, behaviour-focused, attentive to body-image distress and unsafe weight-control behaviours, and linked to referral when mental health or eating-disorder risks are identified. Keywords: Adolescent health, Health education, Obesity, School health services, Weight perception, Vietnamese research.