Defining Clinical Obesity: Distinguishing Risk from Disease

More than a decade has passed since the American Medical Association confirmed that obesity is a complex, chronic disease. But the rest of the world is still struggling with this idea. Much as we have all started to say obesity is a disease, we more often act like it’s merely a risk factor for other diseases. For a real clinical definition of obesity, Francesco Rubino tells us that distinguishing risk from disease is critical:

“The current definition of obesity given and accepted by most organizations is ‘an abnormal or excessive fat accumulation that presents a risk to health.’

“But disease is defined by present illness, not the risk of future illness.

“Clinical obesity is a chronic, systemic illness characterized by alterations in the function of tissues, organs, or the individual, due to excessive or abnormal adiposity.”

Herding Cats, Seeking Clarity

Like herding cats, building consensus among a large, global collection of obesity experts is a near impossible task. But Rubino has taken on this task. He chairs a steering group of eight and leads 58 world-leading experts for the Lancet Commission on Clinical Obesity. The goal is simple – to bring clarity to a clinical definition for obesity. He first began pursuing this goal in 2018.

In a recent ASMBS seminar, Rubino explained the process they are following. For too long, he says, obesity has been defined as a physical phenotype, not a disease. Defining obesity as having a BMI above 30 created as many problems as it solved. A primary problem is that it distracts from the fact of obesity as a chronic disease. It reinforces the unfortunate tendency of people to focus on the superficial appearance of obesity rather than health.

Putting BMI in Its Place

It is taking time to set aside our preoccupation with Body Mass Index. BMI is a very useful tool for epidemiologists. But for the clinical diagnosis of obesity, it is merely one of many inputs. While it can be helpful as an indicator of adiposity and disease risk, it certainly does not define clinical obesity.

For that, we need signs and symptoms of current illness. We look forward to clarity on this from the Lancet Commission on Clinical Obesity.

Click here for Rubino’s recent seminar on this subject, here and here for further perspective.

Risky Society, painting by Jan van Hemessen / WikiArt

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April 9, 2024