BMI Not the right way to measure obesity

Updated Jan 16, 2025 | 11:57 AM IST

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Using BMI To Classify People As Obese Is Flawed Say Experts

SummaryBMI is used to classify individuals as underweight, healthy weight, overweight, or obese based on their height and weight. It is calculated by dividing weight in kilograms by health in meters squared. However, there are reasons while it falls short.

A new report published in The Lancet Diabetes & Endocrinology challenges the conventional definition of obesity, and urges a shift from the reliance on Body Mass Index (BMI) to a more nuanced approach. This is supported by over 50 global medical experts. The report also recommends splitting the term "obesity" into two categories: "Clinical obesity" and "Pre-clinical obesity". This aims to improve diagnosis and treatment for over a billion people worldwide living with obesity.

Clinically Obese

This applies to individuals whose obesity has progressed to a disease state, manifesting in organ damage, heart disease, type 2 diabetes, or other health complications. These individuals could also experience symptoms like breathlessness, joint pain, or impaired daily functioning. Treatment also involves medical interventions, including weight-loss medications or surgery.

Pre-Clinic Obese

Whereas the term "pre-clinic obese" refers to those who are overweight but not yet exhibiting health issues. While they may be at risk of developing obesity-related conditions, their organ function and overall health remain intact. What they need is preventive care, which includes dietary guidance, counselling, and regular monitoring to avoid and reduce future health risks.

What does the study say?

The study, led by Professor Francesco Rubino from King's College London emphasizes that obesity is not one-size-fits-all condition. This means it should rather be treated as a spectrum as some individuals maintain normal organ function despite being classified as obese. There are others who may face severe health complications too. However, the current method of calculating obesity based on BMI often leads to misdiagnosis or inadequate care.

The report also states that BMI, while is useful for analyzing population trends, is a flawed unit of measuring individual health. Therefore, there is a need to redefine obesity, and healthcare professionals can provide more precise care by distinguishing those who need immediate medical intervention and those who require preventive strategies.

Limitations of BMI, Why It Falls Short?

BMI is used to classify individuals as underweight, healthy weight, overweight, or obese based on their height and weight. It is calculated by dividing weight in kilograms by health in meters squared. However, there are reasons while it falls short.

•Muscle vs Fat: Athletes or muscular individuals often have high BMIs despite the low body fat

•Fat Distribution: BMI does not measure fat around the waist or organs, which could be more dangerous to one's health.

•Individual Health Variation: It also overlooks the specific health conditions such as heart diseases or diabetes, or any other, while evaluating a person's category in terms of weight.

ALSO READ: Is It Time To Say Goodbye To BMI?

Scope Of Study

By redefining obesity, the study could transform the approach to diagnosis and treatment. It can focus on individual health risks rather than BMI alone. Healthcare providers can also offer tailored care. This also will ensure hat weight-loss medications like Wegovy or Mounjaro are prescribed only to those who genuinely require it.

As per Professor Louise Baur from the University of Sydney, a Children's obesity expert said that this redefinition allows both adults and children to receive more appropriate care while reducing over-diagnosis and unnecessary treatments.

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