This question came to the Facebook page of our local hospital: "I heard awhile back that a plain ol' waist measurement was a more useful health indicator than BMI (Body Mass Index). Did they change their mind about that again?"
I'm not sure who "they" are who changed their minds. But this is a valid question about the methods used to evaluate our weight in relation to our health. According to the National Institutes of Health (NIH), both measurements have benefits ... and limitations.
Plain ol' waist measurement" is officially called "waist circumference." It is the measurement – in inches – around your middle, just above your hipbones, say experts. This measurement helps identify the presence of dangerous abdominal fat which puts one at increased risk for heart disease and type 2 diabetes. A normal waist circumference measurement for women is less than 35 inches; for men, it is less than 40 inches. Generally as our waist size goes up from normal, so do our health risks.
The waist circumference does have some restrictions, however. According to the NIH, it is not particularly useful in people who are very short (under 5 feet) or very obese (BMI 35 and above).
Unlike waist circumference, Body Mass Index (BMI) is a calculation based on a person's height and weight. It is often used with waist circumference to better predict one's risk for weight-related diseases such as heart disease, high blood pressure, type 2 diabetes and certain cancers. Generally the higher one's BMI, the higher their risk for these chronic diseases.
Here's one way to calculate BMI: Multiply your weight in pounds by 703. Divide that number by your height in inches. Divide that number by your height in inches again. Or go to this link to access an online BMI calculator: https://www.nhlbi.nih.gov/health/educational/lose–wt/BMI/bmicalc.htm.
Body Mass Index is not a good indicator of health status in some people, however. Since it relies on height and weight measurements only, people who are heavy with muscle instead of fat can be erroneously classified as obese. (Bodybuilders and elite athletes come to mind.)
What both these measurements are trying to assess is how much unhealthy fat a person is carrying that affects his or her health. Many practitioners use both methods to draw more precise conclusions.
Beyond these basic and inexpensive tools, there are more advanced techniques to measure the actual composition of our bodies such as fat, muscle, bone, and water. Check out the options with your health care provider.
(Barbara Quinn is a registered dietitian and certified diabetes educator affiliated with Community Hospital of the Monterey Peninsula. She is the author of "Quinn-Essential Nutrition" (Westbow Press, 2015). Email her at to firstname.lastname@example.org.)