When BMI is used to assess weight in adults, the BMI number alone is enough to put the person in a weight category (underweight, normal, overweight, or obese). However, we can not use an adult BMI chart for children since their body fatness changes as they grow. Additionally, girls and boys differ in body fatness, particularly as they mature, so we will need to use gender-specific standards for assessing BMI in kids.
To deal with these differences between adults and children, and between boys and girls, medical care professionals use BMI-for-age-percentile growth charts to interpret BMI in boys and girls ages 2 to 20 years. These charts list ages across the y axis (vertically) and BMI across the x axis (horizontally), and display curves for different BMI percentiles. To use a BMI growth chart, you plot (indicate) the point on the chart where your child’s age and BMI cross, and then take notice of either the percentile curve the point lands on or the curves on each side of this point. The percentiles of these curves become the key to knowing whether the BMI is in a healthy variety. You may use this online graph from the Centers for Disease Control and Prevention.
How do you interpret your child’s or teenager’s BMI percentile? According to pediatric body fat study, medical experts have come up with the following weight classes for children and adolescents:
It is important to point out that “obese” and “heavy” are medical conditions and shouldn’t be used in front of children. It’s best to speak with your child or adolescent about being a healthy weight.