The Death of BMI (Hopefully)
Under recommendations released two weeks ago, obesity would no longer be defined solely by BMI, a calculation of height and weight, but combined with other measurements, such as waist circumference, plus evidence of health problems tied to extra pounds.
IT IS ABOUT TIME!
The Body Mass Index (BMI) has been controversial for a long time and finally decision makers are taking note that there is a better way to identify people who are at risk for diseases caused by excess body fat. I’ve written about how antiquated this tool is multiple times. You can see those articles here and here.
Obesity is estimated to affect more than 1 billion people worldwide. In the U.S., about 40% of adults have obesity, according to the U.S. Centers for Disease Control and Prevention.
The new recommendations came from a report published in The Lancet Diabetes & Endocrinology journal that included 58 international authors. They noted that the idea of obesity as a disease remains highly controversial. In addition, current BMI-based measures of obesity can both underestimate and overestimate adiposity (fattiness) and provide inadequate information about health at the individual level.
The report introduces two new diagnostic categories: clinical obesity and pre-clinical obesity.
People with clinical obesity would be those with a higher than normal BMI and other markers, such as evidence of organ, tissue or other problems caused by excess weight. That could include heart disease, high blood pressure, liver or kidney disease or chronic severe knee or hip pain. These people would be eligible for treatments, including diet and exercise interventions and obesity medications. Other people with any of the 18 medical conditions caused by obesity — 13 for children and adolescents — would also be eligible for medical treatment to improve their health and prevent serious injuries to organs. The conditions include breathlessness, heart failure, hip or knee pain, metabolic abnormalities and poorly functioning organs.
People with pre-clinical obesity are at risk for those conditions based on BMI, but have no ongoing illness, the report says.
The commission said that people who had a BMI over 25 and too much fat, but who are otherwise healthy, should pretty much be left alone. They should be monitored and counseled not to gain any more weight and possibly to lose some.
The simplest way for doctors to see whether someone has excess body fat is to wrap a tape measure around a person’s waist, the group said. If a woman’s waist is more than 34.6 inches, she most likely has too much fat. For a man, a waist the threshold would be at least 40 inches. Other tools for health professionals include waist-to-hip ratios, waist-to-height ratios or DEXA scans, a type of X-ray.

The new definition of obesity has already been endorsed by 76 health organizations around the world. If the guidelines are widely adopted in the United States, they could change doctors’ perceptions of who they need to talk to about their weight and who needs to be treated for obesity. A spokesman for the health insurance trade group AHIP, formerly known as America’s Health Insurance Plans, said “it’s too early at this point to gauge how plans will incorporate these criteria into coverage or other policies.”
BMI has long been considered a flawed measure that can over-diagnose or underdiagnose obesity, which is currently defined as a BMI of 30 or more. But people with excess body fat do not always have a BMI above 30, the report notes. And people with high muscle mass — football players or other athletes — may have a high BMI despite normal fat mass. For reference, my current BMI is around 26, but it has been as high as 30 when I was carrying a lot more muscle and I have never considered myself overweight or obese.

Under the new criteria, about 20% of people who used to be classified as obese would no longer meet the definition, preliminary analysis suggests. And about 20% of people with serious health effects but lower BMI would now be considered clinically obese, experts said.
A possible hurdle with the new definition will be that determining the difference between clinical and pre-clinical obesity would require a comprehensive health assessment and lab tests. In my opinion, these should be part of a routine physical examination or annual checkup already.
Overhauling the definition of obesity will take time, acknowledged Dr. Robert Kushner, an obesity expert at the Northwestern Feinberg School of Medicine and a co-author of the report. “This is the first step in the process,” he said. “I think it’s going to begin the conversation.”
I agree that it will take time, and people will have to be on board. I get that being able to easily measure your height and weight and calculate your BMI is simple. People like simple. But nothing about your body or health is simple. There are just some things that we can’t be lazy about!
Let's hope this leads to some different conversations with people and their healthcare providers around their overall health and wellness.
No comments yet.