New research highlights imperfections of BMI as sole clinical measure

The American Medical Association has adopted a new policy that seeks to remove emphasis on the role of body mass index, or BMI, in clinical practice.

Body Mass Index (BMI), a commonly used measurement to assess weight status and health risks, has come under scrutiny in light of recent research revealing its limitations as a standalone clinical measure.

New studies find that relying solely on BMI may not provide a complete picture of an individual's health and underscore the importance of adopting a more comprehensive approach to evaluating well-being.

Results revealed that BMI, calculated based on an individual's height and weight, fails to account for crucial factors such as body composition, distribution of fat, and overall fitness level.

Basics of Body Mass Index (BMI)

Body mass index is a measurement taken by dividing body weight in kilograms by height in meters squared. The metric rose to prominence for clinicians in the 1990s for physicians to be able to estimate a normal body weight depending on an individual's height.

The World Health Organisation also promoted the adoption of the metric as the official screening index for obesity.

Past research showed that BMI at a population level correlated strongly with body fat percentage and risk for serious health conditions. The index was easy to measure and inexpensive to calculate, allowing its wide implementation in healthcare settings.

However, one of the key limitations of BMI is its inability to differentiate between fat mass and muscle mass. As muscle is denser than fat, individuals with higher muscle mass, such as athletes or individuals engaged in regular strength training, may have a higher BMI.

Though quite physically fit, the BMI would inaccurately categorise them as overweight or obese. Conversely, individuals with a normal BMI may have an unhealthy level of body fat due to a lack of physical activity or a poor diet.

The new policy comes after assessing the significance of fat distribution in assessing health risks.

The accumulation of visceral fat around internal organs has been linked to a higher risk of chronic diseases such as cardiovascular issues and type 2 diabetes. However, BMI needs to capture this vital aspect, as it does not differentiate between subcutaneous fat (located just beneath the skin) and visceral fat.

Moreover, BMI disregards other essential indicators of health, such as blood pressure, cholesterol levels, blood sugar levels, and overall fitness. Focusing solely on BMI may lead to overlooking potential health risks or misclassifying individuals who may appear to have a healthy weight but possess other underlying health issues.

The limitations of BMI have significant implications for clinical practice and public health initiatives. Relying solely on BMI as a measure of health can result in misdiagnoses, inadequate risk assessment, and inappropriate treatment recommendations.

It is crucial to adopt a more holistic approach that incorporates additional measurements, including body composition analysis, waist circumference, and cardiovascular fitness assessments.

By embracing a more comprehensive approach, healthcare providers can tailor interventions and preventive strategies to address specific health risks and empower individuals to make informed decisions about their well-being.

By acknowledging the imperfections of BMI and embracing a multifaceted approach, the healthcare community can better support individuals in achieving optimal health outcomes and pave the way for a more personalised and effective healthcare system.

The American Medical Association supports the need for further research to be conducted on the application of the extended BMI percentiles and its association with other anthropometric measurements, risk factors and health outcomes.

They also call on collective efforts to educate physicians on the issues surrounding purely relying on BMI as the sole health determination tool and are looking for alternative measures for diagnosing obesity.