How Changes to Obesity Diagnosis Affect Workplace Health and Safety
In January 2025, The Lancet Diabetes & Endocrinology Commission published updated diagnostic criteria for obesity, signaling a shift away from relying solely on Body Mass Index (BMI) for diagnosis. This update has sparked discussions in occupational medicine, particularly regarding how obesity is assessed in workplace health and safety evaluations.
BMI and Occupational Medicine: What Changes Matter?
BMI has long been used as a quick and simple metric for assessing obesity, but it has limitations when used in isolation. The new Lancet guidelines recommend that medical practitioners consider broader health factors beyond BMI alone when diagnosing obesity.
However, according to Dr. Sid O’Toole, Occupational and Environmental Physician, the impact on occupational medicine remains minimal:
This distinction is important because occupational medicine is less focused on defining obesity itself and more concerned with how an individual’s weight impacts workplace safety, equipment suitability, and injury risk.
Why Weight Matters More Than BMI in Occupational Medicine
Many employees have undergone pre-employment medical assessments, which typically require them to record their weight and height. But how do these measurements differ in workplace health evaluations?
Key Differences Between BMI and Weight in Occupational Medicine
- Weight = A direct measurement of body mass. This is the primary factor used in workplace safety assessments.
- BMI = A calculation using weight and height (weight ÷ height²) to classify individuals into weight categories. It does not account for body composition, such as muscle mass vs. fat.
Workplace Safety Risks Related to Weight
Occupational and environmental physicians assess weight in relation to:
- Seating capacity and workplace ergonomics – Ensuring employees fit safely into seating designed for specific weight limits.
- Harnesses and safety equipment – Weight restrictions apply to fall protection gear, emergency evacuation systems, and lifting devices.
While BMI may still be used as a risk factor for certain conditions like sleep apnoea, weight is the more critical factor in occupational health evaluations.
High BMI, But Physically Fit? Understanding the Exceptions
One common concern with using BMI is that it does not distinguish between muscle and fat. Professional athletes and physically active workers may have a high BMI but low body fat, meaning their functional health risks differ from those with higher fat composition.
For example, sleep apnoea risk is correlated with BMI due to fat distribution in the neck and upper body, which can narrow airways—even in muscular individuals. This is why a comprehensive occupational health assessment is necessary rather than relying solely on BMI classification.
Why Occupational Health Assessments Go Beyond BMI
In occupational medicine, a person’s entire health and fitness profile must be assessed in relation to their job requirements. This includes:
- Functional capacity evaluations – Assessing a worker’s ability to safely perform their job tasks.
- Cardiovascular fitness and endurance – Particularly for physically demanding roles.
- Musculoskeletal assessments – Identifying risks for joint strain, back pain, and injury prevention.
- Job-specific risk assessments – Ensuring employees meet industry-specific safety standards.
Conclusion: The Role of Occupational Medicine in Workplace Health
While The Lancet’s updated obesity diagnosis criteria provide greater medical clarity, the impact on occupational medicine is limited. Workplace health assessments prioritise weight-related risks over BMI classifications, ensuring employees are fit for work and safe in their roles.
For businesses seeking expert occupational health assessments, Phoenix Occupational Medicine provides:
To learn more about how weight and fitness impact workplace safety, contact Phoenix Occupational Medicine today.
Disclaimer: Information provided is general only and should not construed as legal or medical advice. We recommend that readers seek advice for their specific circumstances.
