The first step to understanding how to answer this question is: What exactly is BMI?
BMI is an acronym for “body mass index” which is a medical calculation in which a person’s height and weight are used to estimate how much fat he or she has on their body.
Tracking BMI starts very early, as young as two-years-old. It is used not to measure body fat, but to identify patterns in a child to determine whether or not they are gaining weight slowly or quickly. Doctor Rima Himelstein says, “It can help screen for potential weight problems that could lead to other health problems.”
Tracking a child’s BMI is different from tracking an adult. A doctor will measure a child’s BMI and instead of looking at it as simply a number, they use it to categorize them into various categories.
These categories are:
● If their weight is in less than the fifth percentile – they are underweight.
● If their weight is more than the fifth percentile and less than the 85th percentile – they are healthy.
● If their weight is in between the 85th and 95th percentile – they are overweight.
● If their weight is equal or greater than the 95th percentile – they are obese.
It is important to note that BMI percentile does not mean a child is at risk for any health issues.
These guidelines are not meant to be the end. It is meant to check on your child’s weight, as their body will fluctuate including their fat levels. Likewise, doctors will take a child’s lifestyle into account, and go from there.
While BMI is an important indicator of your child’s development, it is not a perfect measurement of body fat. If any measurement is taken out of context, it can give you the wrong impression of your child’s growth.
There are plenty of BMI calculators online that you can manually input your child’s information and see where they land. But remember, BMI is not a perfect measurement, but rather it gives parents an idea as to how their child is developing in comparison to other children of their same gender and age.
If you are concerned about your child’s weight, talk to your doctor about your concerns and they will give you a proper BMI measurement to help you understand and navigate what steps to take next.
If you would like more information on BMI, check out our previous blog post.
Gavin, M. (Ed.). (2020, January). Body mass index (bmi) (for parents) – Nemours Kidshealth. Retrieved September 20, 2021, from https://kidshealth.org/en/parents/bmi-charts.html
Crozer Health. (2021). Understanding childhood obesity: How bmi should be used to track weight. Retrieved September 20, 2021, from https://www.crozerhealth.org/news/news-releases/2017/understanding-childhood-obesity-how-bmi-should-be-used-to-track-weight/
CDC. (2021, June 07). BMI calculator child and teen. Retrieved September 20, 2021, from https://www.cdc.gov/healthyweight/bmi/calculator.html
Author: Sophia Galvez
Editor: Anum Khan
Public Health scientist: Hira Mughal