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Multidisciplinary Support: Body Mass Index
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Body Mass Index

What Is the Body Mass Index (BMI)?

The Body Mass Index, or BMI, is a standard measurement comparing a person’s height to their weight. The BMI is a very useful tool in determining a person’s healthy weight range. The BMI measurement is limited in that weight coming from muscle is still measured as weight. For example, an athletic person can have significant muscle mass and very little body fat which will result in a higher BMI due to their overall weight. 

At any given height, a BMI range of 20–25 is within normal limits for an adult. A score of 19 or lower is considered underweight. Values above 25 are considered overweight. The same does not hold true for children and young adults ages 2–20. It is important to understand that BMI in adults and children may be calculated the same, but do not hold the same value. A further step must be used for children and young adults; they must have their BMI Percentile calculated. BMI alone should not be used to determine whether a child or young adult is at a healthy weight.