BODY MASS INDEX (BMI) NO LONGER PERTINENT

More than 40% of U.S. adults are obese. I suspect 40% is low and it’s more like 50%-60% of Americans who fall into that category. All of us know how easy and “fun” it is to gain weight and how difficult and painful it is to lose weight. Losing weight requires lifestyle changes, a sense of feeling hungry all the time, and the denying yourself of things you enjoy. It’s a very slow process, too. 

Recently, an international commission redefined obesity into “clinical obesity” and “preclinical obesity” and de-emphasized the use of Body Mass Index (BMI). In fact, waist circumference (WC), waist-to-height ratio (WHtR), and hip circumference (HC) are the most accurate measurements for determining obesity, and for detecting the risk for diabetes, cardiovascular disease, and infertility. These are components of the anthropometric risk index (ARI), “a highly effective predictor of cardiovascular disease.” What do these designations mean?

Clinical Obesity is a condition where the excess fat on one’s body is a risk to health and is already visible and measurable. “If the patient has metabolic syndrome, diabetes, arthritis, or functional limitations due to their obesity, they have clinical obesity.”

Preclinical obesity is obesity that has not altered the functioning of the body.

Body Mass Index (BMI) is an imprecise measure. It ignores body fat distribution and lean body mass and doesn’t determine risk. BMI both overdiagnoses and underdiagnosis obesity. Many people with a high BMI are not clinically obese, but have a maldistribution of fat in  localized areas. 

Instead of height vs. weight on a chart determining BMI, the commission recommends either direct body fat measurement with specific equipment designed to accurately determine obesity, or anthropometric criteria—“a set of measurements used to assess body composition and nutritional status.” (See above). This is much more precise and accurate and prevents misclassification. It requires a bit more effort to complete measurements, but accuracy is the benefit. 

So, what do ya know! With a BMI of 35 maybe I’m not really obese. But looking in the mirror, I think the diagnosis is a certainty. 

Reference: Skolnik N. Bench the BMI? New Guidance Redefines Obesity. Medscape Family Medicine 2025 January 29.

Hewage N, Wijesekara U, Peter’s R. Determining the method for evaluating obesity and the risk for non communicable diseases in women of childbearing age by measuring the body mass Index, waist circumference, waist-to-hip ratio, waist-to-height ratio, A body shape index, and hip index. Nutrition 2023 October;114:112135.