New definition of the concept of ‘obesity’

The report was published in the journal The Lancet Diabetes & Endocrinology on January 14, said that the definition of obesity should be based on the amount of body fat and medical complications of the patient, instead of relying solely on weight. 76 organizations around the world have endorsed this new definition.

Previously, BMI below 18.5 was underweight and needed to gain weight and receive nutritional supplements. BMI between 18.5 and 25 is the limit for people with normal bodies, all indicators are at a good level. BMI between 25 and 30 is overweight. BMI over 30 is obesity and increases the risk of diseases caused by obesity.

After conducting new research, a committee of 58 doctors proposed that, in addition to BMI, other factors such as excess fat and underlying disease complications should be considered. The report clearly states that people with BMI over 25 and excess fat should be monitored and advised not to gain or lose weight. This condition is called clinical obesity. People with diseases such as difficulty breathing, heart failure, hip and knee pain, metabolic disorders, and impaired organ function need medical treatment. People with a BMI of 40 or more can be diagnosed with clinical obesity, without needing to assess body fat.

The simplest way for doctors to check for excess fat is to measure waist circumference. Waist circumference over 88 cm in women and 101.6 cm in men is often due to excess fat. Other tools include measuring waist-to-hip ratio, waist-to-height ratio, or a DEXA scan (the most common method to measure osteoporosis).

58 experts spent years on this report. Dr Francesco Rubino, chair of the committee and a bariatric surgeon at King’s College London, said the group wanted to assess obesity differently, rather than treating it as a disease.

The American Heart Association (AHA) endorsed the report. Dr. Mariell Jessup, the association’s chief medical and scientific officer, said doctors have previously struggled with imprecise methods for judging a person as obese.

Rebecca Puhl, deputy director of the Rudd Center for Policy, Food and Health at the University of Connecticut, said the committee is “trying to alleviate some of the misconceptions about obesity.” This could reduce stigma, as obesity is still considered a character flaw, rather than a complex health problem.

However, widespread adoption of the new definition of obesity may be difficult. For many years, experts said the world relied too heavily on BMI to determine overweight and obesity. This index is easy to measure, only requires height and weight. It quickly became the standard for determining whether people were underweight, overweight or not.

Dr. David M. Nathan, professor of medicine at Harvard and founder of the diabetes center at Massachusetts General Hospital, said BMI is a major risk factor for diabetes, heart disease, and cancer. Waist circumference also plays a similar role. But unlike BMI, doctors sometimes ignore this factor.

According to Dr. Nathan, the expectation that “the whole world will change its view on obesity according to the new definition” is unrealistic. Besides, waiting until there are health complications to treat obesity is too late.

“That’s like saying, don’t treat high blood pressure until the patient has a stroke,” Dr. Nathan said.

Changing obesity diagnostic criteria also affects new and upcoming treatment drugs on the market.