Beyond BMI: Rethinking obesity diagnosis

A recent report by The Lancet Diabetes & Endocrinology Commission calls for a shift in obesity diagnosis, proposing a more comprehensive and clinically relevant approach

For decades, Body Mass Index (BMI) has been the go-to metric for diagnosing obesity. However, BMI is a blunt tool that doesn’t distinguish between fat and muscle, fails to consider fat distribution, and overlooks critical signs of health or illness. This has led to widespread under- and over-diagnosis of obesity, misinforming patients and leaving many at risk.

Why current BMI-based obesity diagnosis falls short

• Lack of precision: BMI measures body weight relative to height but does not differentiate fat from muscle.
• Example: Athletes with high muscle mass often receive false-positive obesity diagnoses.
• Inadequate Risk Assessment: Obesity’s health risks stem from fat’s effects on organs, which BMI cannot assess.
• Ethnic discrepancies: BMI thresholds vary across ethnicities, rendering “one-size-fits-all” metrics inadequate.

A new framework: preclinical vs. clinical obesity

To address these limitations, the Commission introduces two new categories:

Preclinical obesity:

• Defined as excess body fat without ongoing illness.
• Individuals remain functional but face elevated risks of future diseases such as Type 2 diabetes, cardiovascular issues, and clinical obesity.

Clinical obesity:

• A chronic condition where excess fat impairs organ function or daily activities.
• Associated with symptoms like breathlessness, joint pain, or metabolic abnormalities.

A more comprehensive diagnosis process

Health professionals are encouraged to shift focus from BMI to a three-step diagnostic approach:

1. Confirm excess fat: Use waist circumference, waist-to-hip ratio, or advanced scans (e.g., DEXA) to assess fat levels.
2. Assess health impact: Evaluate symptoms of organ dysfunction (e.g., kidney issues, mobility limitations).
3. Establish the root cause: Determine whether observed dysfunctions are obesity-related.
4. Personalised management strategies.

Preclinical obesity:

• Focus on prevention through health counseling and weight stabilisation.
• Active weight-loss interventions for high-risk patients.

Clinical obesity:

• Treat organ dysfunction through targeted interventions.
• Success should be measured by functional improvement, not weight loss alone.

Implications for stakeholders

For healthcare providers:

Transitioning to the proposed model will require additional training in advanced diagnostic techniques and patient-centered care.

For payers and policymakers:

Adopting evidence-based frameworks can optimise healthcare costs by focusing on prevention and tailored interventions.

For businesses (e.g., pharmaceutical, wellness companies):

The demand for tools like DEXA scanners, wearable health monitors, and personalised treatments is likely to grow.

A step forward in combating obesity

This new approach marks a shift from treating obesity as a one-dimensional condition to addressing it as a spectrum of health risks and illnesses. By embracing this model, healthcare professionals can provide more precise, effective, and compassionate care, ensuring better outcomes for patients.