The body mass index, or BMI, is a numerical representation of body fat based on weight and height and applies to all genders. You can find several calculators online to help you determine your BMI, or you can use a simple formula: BMI = (weight in pounds x 703)/(height in inches x height in inches).
Any result between 18.5 and 24.9 is normal; above 24.9 is obese, and below 18.5 is underweight. However, what do these numbers mean, and are they an accurate measurement of health?
Reviewing the Numbers and Their Meaning
If you are old enough, you will remember seeing charts in doctors' offices recommending ideal weights for different heights and body shapes. The charts developed from calculations and actuarial statistics used by life insurance companies. The "ideal weights" supposedly determined the individual's likelihood of reaching old age.
Medical professionals and services eventually scrapped the cumbersome charts. Not only were the tools impractical, but there was never any clear direction about determining frame size.
BMI became the new normal when determining ideal weight, but it is not new. The calculation is roughly 200 years old, but it is relatively new to the practice of healthcare.
Still, medical professionals argue BMI is not perfect. While the formula is a decent representation of health in general, its simplicity has some pretty obvious flaws. For one, pregnant women and those with high muscle mass can throw off the calculation. Also, the calculation is relatively useless for children and the elderly. However, in general, BMI is a decent indicator of an individual's risk factors for certain conditions when the number is accurate. For example, higher BMIs indicate an increased risk of developing several conditions, including:
Arthritis
Diabetes
Hypertension
Liver disease
Sleep apnea
High cholesterol
Certain cancers
BMI Is Not a Comprehensive Guide
Research shows BMI measurements often misclassify metabolic health — a measurement of fat and how it's distributed. Also, the single number is unreliable for various sections of the population, such as pregnant women, the elderly, and athletes.
Additionally, BMI is not a good measure of current health issues; instead, it is an indicator of potential future health crises. As a single measure, BMI cannot identify various issues like blood pressure, blood sugar, cholesterol, or overall cardiovascular health.
The current BMI calculation is not suitable for all audiences. The basis of the current measurement is a largely white population. Therefore, if BMI is the sole basis of counseling, the number can lead Black and Asian individuals astray. According to health officials, the current BMI measure can underestimate obesity risks to Asians and overestimate the risks to Black populations.
Medical professionals rarely rely on BMI for a complete measure of your health. However, it is still a useful tool under the right circumstances.
Your BMI is only one tool to measure your overall health, but it is not the most effective. It is best to use BMI as a risk assessment, but even that is ineffective depending on your age, gender, ethnicity, and other underlying factors. Ultimately, BMI is only one way to measure your health, but it is not the most accurate.