Adolescent Medicine

Determining Body Mass Index

What is body mass index?

Determining how much your adolescent should weigh is not a simple matter of looking at an insurance height-weight chart, but includes considering the amount of bone, muscle, and fat in his/her body's composition. The amount of fat is the critical measurement.

A good indicator of how much fat your adolescent carries is the Body Mass Index (BMI). Although it is not a perfect measure, it gives a fairly accurate assessment of how much of your adolescent's body is composed of fat.

To calculate your BMI using the English formula:

BMI can be calculated using pounds and inches.
 
BMI =              Weight in Pounds                          x  703
            (Height in Inches) x (Height in Inches)
 
For example, a person who weighs 165 pounds and is 5 feet 4 inches tall has a BMI of 28.
 
                       165 lbs                            x 703 = 28
      (64 inches) x (64 inches)

To calculate your BMI using the Metric formula:

BMI can be calculated using kilograms and meters.
 
BMI =              Weight in Kilograms                       
        (Height in Meters) x (Height in Meters)
 
For example, a person who weighs 99.79 Kilograms and is 1.905 Meters tall has a BMI of 27.5.
 
                          99.79 Kg                        = 27.5
       (1.905 Meters) x (1.905 Meters)

A BMI between 25 to 29 is considered overweight. Anything over 30 is considered obese.