Learn about Childhood/Adolescent Obesity

Measuring Weight in Children and Adolescents

When visiting your pediatrician, you will hear them talk about BMI, BMI-for-age percentiles and growth while discussing your child’s weight or obesity. It’s important to familiarize yourself with these terms as these are used to determine your child’s weight status category.

BMI-for-age Percentiles 

Obesity in children (referred to as “overweight” in the weight status category table) is determined by using BMI-for-age percentiles. BMI-for-age percentiles have emerged as the favored method to measure weight status in children. This method calculates your child’s weight category based on age and BMI, which is a calculation of weight and height. However, it should be kept in mind that this method, among other methods, should be used as a tool, and only a physician can best determine and diagnose weight status in your child.

To plot a child’s BMI-for-age percentile, you must first calculate his/her BMI. To locate a BMI chart with weights and heights appropriate for children, please click the below link. Once you calculate his/her BMI, find the age of the Add Newchild on the bottom of the BMI-for-age percentile chart (click on below link for boy or girl) and look to the left or right to locate their BMI.

Plot the point on the graph using a pen or pencil. Once you have plotted the measurement, locate the corresponding shaded color on the bottom of the chart to determine your child’s BMI-for-age percentile. You are then able to find your child’s weight status by viewing the Weight Status Category table located to the right of the chart.

Measuring Growth in Children

You may have heard your pediatrician refer to your child’s weight in terms of a percentile. To measure growth in your child based on their weight, doctors most commonly use weight-for-age percentiles. Weight-for-age percentiles are used to measure your child’s weight based strictly on age. It does not take into account the height of a child. This is not a method to determine obesity (or overweight) in children, but simply an indicator of growth as compared to children of the same age.

To plot your child’s weight-for-age percentile, find the age of your child on the bottom of the chart and look to the left to locate their body weight. Once you locate their weight and age, plot the point on the graph using a pen or pencil. Once you have plotted the measurement, locate the corresponding shaded color on the bottom of the chart to determine your child’s weight-for-age percentile.

Once you have found your child’s weight-for-age percentile, you can then determine what percentile (or percentile range) they fall into, as compared to children of the same age. For example, if your child is in the 95th percentile, this means that their weight is greater than 95 percent of children of the same age.

If your child’s BMI is not listed on the charts above, please click here to calculate their BMI.

*Disclaimer: You cannot measure children’s weight using solely BMI. You must calculate BMI and then plot it on the BMI-for-age percentile graph to find the child’s weight status*

To learn more about childhood obesity, click here.

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