Why more Americans may soon be diagnosed with obesity

The U.S. obesity rate will increase from 42.9% to 68.6% if the new body mass index (BMI) definition is implemented.

The Lancet Diabetes and Endocrinology Commission recommends updating the BMI definition to include body fat distribution measures, instead of focusing on weight alone. This marks an important evolution in defining obesity.

How the proposed new BMI works 

The body fat distribution measures, known as anthropometric measures, are waist circumference, waist-to-height ratio and waist-to-hip ratio. These measures identify excess body fat, which is linked to diabetes, hypertension and cardiovascular disease. 

Based on the proposed definition, a person would be considered obese if they have a physical impairment or organ dysfunction, a BMI above 30 and at least one elevated body fat measure. A person could also be considered obese if they have a physical impairment or organ dysfunction, a normal BMI and two elevated body fat measurements. 

“This is a step in the right direction in how we care for patients with obesity,” says Dr. Gessa Therese Suboc, an obesity medicine physician at Advocate Health Care. “I appreciate that the emphasis is shifting toward obesity as a disease of excess body fat rather than weight alone.” 

Incorporating body fat measurements into the BMI criteria provides a clearer picture of the potential health risks of obesity, which include diabetes, cardiovascular issues and overall mortality. 

“A new obesity diagnosis can be a challenging conversation, but I’m encouraged that the focus is moving away from a number on the scale toward how excess body fat and fat distribution affect one’s health,” Dr. Suboc says.

But a lower weight doesn’t always mean you are healthy. 

“Someone with a smaller frame can still have significant excess body fat-related metabolic risk,” Dr. Suboc explains. “In those cases, you want to preserve skeletal muscle mass, especially when the BMI is already low, and focus on reducing fat mass. That is a very different clinical conversation.”   

A new approach to obesity care

These proposed definitions pave the way for a new approach to obesity care – one that reduces stigma, fosters compassion and ensures patients receive support based on a clearer picture of their health.  

“The more consistently we recognize obesity as a clinical diagnosis rooted in excess body fat, the better positioned we are to treat patients effectively and address the chronic diseases that accompany it,” Dr. Suboc shares. 

Need help managing your weight or BMI? Find a weight management doctor in Illinois or Wisconsin.