Body Mass Index (BMI) is a number calculated from your weight and height which makes it an inexpensive and easy screening for weights that may lead to health problems. Go to the National Institutes of Health website for a BMI calculator.
Calculating BMI is easy, but figuring out what your BMI means is the hard part. First BMIs are not meant to be a stand-alone diagnostic tool. Assessing health at a particular weight for an individual requires evaluations of diet (undereating or overeating), muscle development (high muscle density increases body weight), family history (genetics explain about 70% of body weight), and heart rate (too low body weight is associated with dangerously low heart rates), hormone status (too low body weights interferes with menses and lowers testosterone), blood pressure, and other health measures.
As I mentioned several weeks ago here, the US has adopted the World Health Organizations (WHO) BMI categories which I believe are set too low to be applied to most Americans. A number of researchers agree that the standard US BMI weight categories for adults are problematic in many areas, particularly, if applied indiscriminately to eating disordered patients.
The standard BMI categories underestimate the presumed health consequences of lower weights and overestimate the presumed health consequences of higher weights. Recent studies of US mortality rates find that people in the overweight and obese categories according to the standard BMI categories have lower mortality rates than have been previously estimated. In fact the lowest mortality rates are in the standard BMI “overweight” category (BMI 25–29.9). The standard categories, however, are sometimes helpful in evaluating weights of people of Asian descent.
Here are the current standard US BMI weight categories:
Standard BMI Categories
|
Weight Status Category |
BMI Range (kg/m2) |
|
Underweight |
Below 18.5 |
|
Healthy weight |
18.5 to 24.9 |
|
Overweight |
25 to 29.9 |
|
Obese |
30 or greater |
Never willing to wait around until governments see the light, I have revised the standard BMI categories and added several new categories. My revisions are based on a thorough review of the research and account for gender and musculature. (References on request.) I have used these revised BMI categories for over 15 years in clinical practice with great success.
I defined a minimum safe weight as the lowest weight at which a person can maintain healthy function (including regular periods for women and normal testosterone levels for men), meet nutritional needs, and not engage in eating disordered behaviors and thinking.
To use my revised BMI categories go to the BMI calculator for adults @ http://www.nhlbisupport.com/bmi/ and then find your category in the chart below:
Revised BMI Categories for Adult Females
|
Weight Status Category |
Percentile Range (kg/m2) |
|
Risky Low Weight |
Below 18.5 |
|
Low Weight |
18.5 to 19.9 |
|
Minimum Safe Weight |
20 to 24.9 |
|
Safe Weight |
20 to 29.9 |
|
Risky High Weight |
30 or greater |
Revised BMI Categories for Adult Males
|
Weight Status Category |
Percentile Range (kg/m2) |
|
Risky Low Weight |
Below 20 |
|
Low Weight |
20 to 24.9 |
|
Minimum Safe Weight |
22 to 30 |
|
Safe Weight |
25 to 34.9 |
|
Risky High Weight |
35 or greater |
In my next blog, I will talk about BMI categories for children and teens.
Marcia
Nutritionist Marcia Herrin and Nancy Matsumoto, co-authors of The Parent’s Guide to Eating Disorders, Gūrze Books. Marcia is also author the soon to be published Nutrition Counseling in the Treatment of Eating Disorders (September, 2012). Read more from Marcia and Nancy by clicking here.
Copyrighted by Marcia Herrin and Nancy Matsumoto
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