One of the nation’s most widely read health publications has announced that it’s saying goodbye to BMI. “Prevention and our sister publication Good Housekeeping will not be using Body Mass Index in our discussions of health anymore,” said the editors this month.
BMI is determined by dividing a person’s weight, in kilograms, by the square of their height as measured in meters. Adolph Quetelet, who originated the concept of BMI in the nineteenth century, studied growth rates over time and concluded that as people mature, their weight increases in proportion to the square of their height.
Quetelet’s interest was understanding the development of the human body, and BMI was designed as a measurement of this, not of health. While the CDC’s web page about BMI suggests that there are some correlations between it and unwanted health conditions, it also acknowledges that BMI, “does not diagnose the body fatness or health of an individual.”
In a study published in 2016, researchers at the University of California considered whether it was fair for employers to require workers to pay more for health insurance based on high BMI numbers. Examining the records of over 40,000 participants in the annual National Health and Nutrition Examination Survey, they found that half of those classified as “overweight” according to their BMI were metabolically healthy, as were almost a third of those with “obese” BMI numbers.
Moreover, almost one in three with “normal” BMI scores were metabolically unhealthy. “Using BMI categories as the main indicator of health, an estimated 74,936,678 US adults are misclassified as cardiometabolically unhealthy or cardiometabolically healthy,” they concluded.
As discussed in earlier eSavvyHealth news briefs, BMI does not distinguish between muscle mass and fat, or reflect normal, healthy, variations associated with gender and ethnicity.
If Prevention has cast BMI aside, what numbers should you use? The best way to answer that question might be to improve your understanding of the basics of healthy metabolism. The free Guidebooks and the video courses that eSavvyHealth has created to help with this can be found here.