Diagnosing Obesity

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Clinical Obesity

Obesity is a chronic and serious health condition. Historically, it was defined as excess body fat that poses a risk to health. However, this definition is limited because obesity is more than just a risk factor—it is a disease in its own right, and some people with obesity develop health problems directly as a result of the condition.​ In 2022, a Lancet Commission aimed to provide a clearer definition of obesity. Their findings, published in January 2025, introduced two categories of obesity:

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• Pre-clinical obesity: excess body fat with preserved function.

• Clinical obesity: a chronic systemic illness characterized by changes in the function of tissues, organs, or the entire body due to excess body fat.

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Check out the blog to read more about the Lancet Commission's new definition of obesity.

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Body Mass Index (BMI)

Traditionally, obesity has been diagnosed using BMI, which measures weight relative to height. For Caucasians, a BMI of 30 or above typically indicates obesity. However, BMI doesn’t account for variations between ethnic groups, and someone of South Asian descent, for example, may be classified as obese with a BMI above 27.

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BMI has limitations:

• It doesn’t show where fat is distributed. Visceral fat (fat around organs) is more dangerous than fat stored in the limbs.

• It doesn’t distinguish between fat and muscle. A muscular person (like a rugby player or weightlifter) may have a high BMI but little body fat.

 

Accurate Diagnosis

At Perth Weight Clinic, we use a combination of BMI, anthropometric measurements, and bio-impedance testing for an accurate picture of your body fat and its distribution. We may also reccomend DEXA imaging for accurate assessment of fat and muscle mass composition.​​​