Agreement Between Body Mass Index and Body Fat in Adolescents With Different Physical Activity Levels

Purpose: This study aimed to verify the agreement between body mass index (BMI) and body fat in adolescents with different physical activity (PA) levels. Method: This cross-sectional study collected body fat data in 118 adolescents (aged 10 to 14 years) estimated using air-displacement plethysmography (ADP). Body mass 10 and height were used to calculate BMI. Physical activity levels were measured objectively by accelerometers. Results: For boys with low PA, BMI overestimated body fat values measured by ADP (mean error = -0.42; p = .018) which also occurred in group high PA (mean error = -0.76; p = .001). For girls, BMI underestimated body fat values measured by ADP values in group high PA (mean error = 0.43; p = .001) and low PA (mean error = 0.72; p < .001). Conclusion: It is recommended that researchers and practitioners 15 cautiously interpret BMI results, especially considering that most adolescents do not practice enough PA.

Automated summary

This study aimed to verify the consistency between BMI and body fat in adolescents with different levels of physical activity. The results showed that BMI overestimated body fat values in boys with low physical activity and in both boys and girls with high physical activity. On the other hand, BMI underestimated body fat values in girls with high and low physical activity. These findings highlight the importance of cautious interpretation of BMI results, especially considering the inadequate physical activity levels among adolescents.