Thought Leadership

Rethinking Health Metrics: Obesity related Cancer and the use of BMI

In recent years, research has highlighted the profound impact of obesity on cancer, linking it to 32 types of cancer and suggesting it fuels 40% of cases. However, our reliance on Body Mass Index (BMI) as a primary health metric is questionable at best. Originating from a 200-year-old arbitrary statistical ratio, BMI fails to account for critical factors such as muscle mass and fitness levels.

In this thought leadership piece, our CEO Nathan McNamara delves into the limitations of BMI and advocates for a shift towards more accurate and actionable health metrics.

The Limitations of BMI

The Limitations of BMI

BMI, a simple ratio of weight to height, fails to distinguish between muscle and fat, leading to potential misclassifications. For instance, athletes with high muscle mass often register as overweight or obese according to BMI, despite having low body fat and being in excellent health. This discrepancy underscores BMI’s limitations in providing a true picture of an individual’s health.

Research shows that muscle density, or lean muscle mass, is a more reliable health indicator. Higher muscle mass is associated with improved metabolism, greater physical strength, and better overall health outcomes. Studies indicate that increased muscle density correlates with reduced risks of cardiovascular diseases, diabetes, and mortality.

The Superiority of VO2 Max

The Superiority of VO2 Max

VO2 Max, the maximum rate of oxygen consumption during intense exercise, is a robust measure of cardiovascular fitness and overall health. It reflects how efficiently the body uses oxygen, providing insights into aerobic endurance. High VO2 Max levels are linked to lower risks of chronic diseases, including heart disease and certain cancers.

Unlike BMI, VO2 Max directly measures physical fitness, making it a superior metric for health assessment. Enhancing VO2 Max through regular cardiovascular exercise can significantly improve metabolic health, boost energy levels, and reduce the risk of lifestyle-related diseases.

Fitness and Mortality: A Clear Correlation

Fitness and Mortality: A Clear Correlation

Studies consistently show that higher fitness levels correlate with lower mortality rates. The most significant difference is observed between the least fit 25% of the population and everyone else. Simply moving from a low fitness level to a slightly better one, and then to even higher levels, dramatically reduces the risk of death from any cause. For instance, comparing individuals with low fitness to those with elite fitness reveals a five-fold difference in mortality over a decade.

This difference is profound when considered alongside other well-known mortality risk factors such as smoking, coronary artery disease, Type 2 diabetes, hypertension, and end-stage renal disease. Low fitness levels increase mortality risk by 41% over a decade, with specific risks including a 29% increase from coronary artery disease, 40% from diabetes, 21% from hypertension, and a staggering 180% from end-stage renal disease.

Comparatively, the impact of improving cardiorespiratory fitness from the bottom 25th percentile to above average (50th to 75th percentile) matches the mortality reduction seen in eliminating major risk factors. Achieving this improvement is attainable with moderate exercise: I.e. 18-30 minutes of activity per day at an intensity that leaves you slightly out of breath but still able to speak.

Shifting the Focus to Muscle Density and VO2 Max

Shifting the Focus to Muscle Density and VO2 Max

Given these insights, it’s imperative to shift our focus from BMI to muscle density and VO2 Max as primary health indicators. Public health policies and individual fitness goals should prioritise these metrics to address health risks more effectively.

For effective health monitoring, regular assessments of muscle density and VO2 Max can provide actionable insights. This approach enables individuals to tailor their fitness routines to build muscle mass and improve cardiovascular health, ultimately reducing the incidence of obesity-related diseases.

By focusing on these metrics, we can develop more effective strategies for disease prevention and health promotion, ensuring better health outcomes for individuals and reduced inequality in our population.

Date Published: 28 May 2024

View our Sector Brochures

Thanks for signing up.

We’ll be in touch shortly.