How Big a Deal is BMI?

Most of today’s parents grew up thinking about weight management in terms of calories and pounds.  We all knew how many calories we were supposed to be eating and how many pounds we were supposed to weigh.  We were taught about counting calories but today’s weight management buzzword, BMI, wasn’t part of our weight management vocabulary.  BMI is actually three words, Body Mass Index, and it is a screening tool that can be used to gauge where someone falls on the weight continuum.  It is calculated using your height and weight and shows whether you are underweight, overweight, obese, or at a healthy weight.

With all the buzz about BMI, many parents are left wondering whether or not it is a big deal and how it applies to their teenagers.   Here are the basic facts about BMI.

What is Body Mass Index?

According to the Center for Disease Control, body mass index is a cost effective and reliable method for determining body fatness for people of all ages, including children and teens.  While there are other methods for measuring body fat that are more precise, BMI is a simple, easy, no cost way to screen for possible weight related health problems.

How is it Calculated?

BMI is calculated by dividing a person’s weight by their height squared.  You can easily get your BMI without having to do any math by using the BMI Calculator for adults provided by the CDC.  To find the BMI for a child or teenager, use the CDC’s BMI calculator designed specifically for them.

How is BMI Read?

BMI is represented as a number that corresponds to a specific weight category ranging from underweight to obese.  For children and teens, this number is associated with a percentile that corresponds to where that BMI falls in these categories.  Adolescents with a BMI below the 5^th percentile are considered underweight.  Those who fall between the 5^th and 85^th percentile have a healthy weight.  A BMI from the 85^th to the 95^th percentile are considered overweight and anyone with a BMI in the 95^th percentile and above is obese.

The difference between how BMI is calculated for adults and for adolescents reflects the fact that body fat changes with age and across genders as children grow into adults.

What BMI Should Your Teen Have?

As outlined above, because of the considerable changes experienced as adolescents grow from childhood into adulthood, healthy weight should be gauged by your teenager’s BMI percentile.  Using the BMI calculation and categories specific to teenagers accounts for the differences caused by gender, age, puberty, and height.  If you are concerned that your teenager’s BMI percentile is outside the healthy weight range, it is a good idea to discuss your concerns with their primary care physician or a registered dietitian.  Additional testing may be needed to determine actual body fatness which can be ordered or conducted by these medical professionals.

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• How to Talk to Teens About Weight (doorwaysarizona.com)
• Working Towards Wellness (doorwaysarizona.com)
• How Many Calories Should My Child Be Eating? (doorwaysarizona.com)