Wisdom and Understanding Audio Story Series

Redefining Obesity: 

A Shift Toward Comprehensive Health Assessment

 A global panel of health experts has put forward new recommendations aimed at broadening the definition of obesity beyond the widely used body mass index (BMI) metric.

These guidelines originate from the Commission on Clinical Obesity, comprising numerous medical professionals from diverse specialties worldwide. The commission advocates for the integration of body fat assessments and existing health conditions, emphasizing that BMI should not be the sole indicator of an individual's health status.

Additionally, the proposal suggests differentiating between "pre-clinical" and "clinical" obesity to enhance the evaluation and management strategies for obesity.

Pre-clinical obesity is characterized by an accumulation of excess body fat without any impairment of organ function, though there is an elevated risk of progressing to clinical obesity and facing long-term health issues, such as cardiovascular disease and Type 2 diabetes.

Dr. Robert Kushner, a commissioner and professor of medicine and medical education at Northwestern University's Feinberg School of Medicine, explained in an interview with ABC News, "In essence, their organs are functioning properly, they do not have metabolic diseases, and their overall quality of life is fairly good." 

In contrast, clinical obesity is characterized by excessive body fat that adversely impacts organ function or hinders an individual's ability to perform everyday activities. This condition can result in serious health risks, including heart attacks, kidney failure, and strokes.

Dr. Kushner noted, "The additional body fat is affecting the individual's health or quality of life."

The report also details the diagnostic criteria for obesity, which merges a high BMI with at least one abnormal body fat measurement, including waist circumference, waist-to-hip ratio, waist-to-height ratio, or elevated direct body fat measurements obtained through imaging.

Importantly, an individual may still be classified as obese if they display two or more abnormal body fat metrics, regardless of their BMI.

As defined by the World Health Organization, obesity in adults is determined by a BMI of 30 or higher, impacting approximately 1 in 8 adults. However, relying solely on BMI for obesity diagnosis has certain limitations.

“BMI does not account for body composition or the proportion of body weight that is fat, nor does it consider the fat's distribution within the body,” explained Dr. Louis Aronne, director of the Comprehensive Weight Control Center at Weill Cornell Medicine, in correspondence with ABC News. “This means that a person can be of normal weight but still have a high percentage of body fat, placing them at risk for clinical obesity. Conversely, an individual may have a high BMI but a relatively low percentage of body fat.”

The commission emphasized that obesity is a chronic disease with significant health implications.

“This is primarily a physical issue rather than a mental or behavioral one. As a disease, obesity can lead to or exacerbate multiple other health conditions. Weight loss can simultaneously improve all these conditions," Dr. Aronne noted.

He also mentioned, "Recognizing that some individuals are already facing complications from obesity (clinical) allows us to focus more intensive and costly treatments on them, which makes sense from a cost-effectiveness perspective. Meanwhile, those who have not yet reached that stage (pre-clinical) can begin treatment with less intensive and more affordable options."

It remains uncertain when, or if, these recommendations will be widely implemented in the healthcare community.

“We're working to spread this message,” said Dr. Kushner. “Our goal is to move away from a one-size-fits-all diagnosis of obesity based solely on elevated BMI. It is crucial to identify individuals who are negatively affected by their weight.”

This report also included contributions from Dr. Brent Gawey of ABC News.

Dr. Jennifer Miao, a board-certified cardiologist and critical care fellow at Yale School of Medicine/YNHH, is part of the ABC medical news unit.