BMI interpretation for children and teens requires special consideration of age, sex, and growth patterns. Understanding these differences helps parents support healthy development.
Key takeaways
- Children's BMI is evaluated using age- and sex-specific percentiles, not fixed categories.
- Growth spurts and puberty significantly affect BMI interpretation in young people.
- Focus on healthy habits rather than weight numbers when working with children and teens.
How pediatric BMI differs from adult BMI
Children's BMI is plotted on growth charts that account for normal growth patterns and puberty-related changes.
The same BMI number can mean different things for a 10-year-old versus a 16-year-old, even of the same sex.
- Uses CDC growth charts for ages 2-19
- Expressed as percentiles, not categories
- Considers normal growth variations
Understanding BMI percentiles for kids
BMI percentiles compare your child to others of the same age and sex. A 50th percentile means your child is average for their age group.
Healthy ranges are generally 5th to 85th percentile, with underweight below 5th and overweight above 85th percentile.
- Underweight: <5th percentile
- Healthy weight: 5th-85th percentile
- Overweight: 85th-95th percentile
- Obese: >95th percentile
Special considerations for teens
Puberty causes rapid changes in body composition that can temporarily affect BMI percentiles.
Focus on establishing healthy eating and activity patterns rather than specific weight goals during this period.
- Growth spurts affect BMI temporarily
- Focus on habits, not numbers
- Encourage body positivity and self-acceptance
Action steps to take next
- Use age-appropriate BMI calculators designed for children and teens.
- Track BMI percentiles over time rather than focusing on single measurements.
- Work with pediatricians to interpret results and develop healthy lifestyle plans.
Health questions answered
When should I be concerned about my child's BMI?
Consult your pediatrician if your child's BMI is consistently below the 5th percentile or above the 85th percentile, or if you notice rapid changes.
Can teens use adult BMI categories?
No, teens should use age- and sex-specific percentiles until age 20, when adult BMI categories become appropriate.