For decades, Body Mass Index (BMI) has been the standard for diagnosing obesity. A simple calculation of weight divided by height squared, it categorises individuals as underweight, normal weight, overweight or obese. But is it truly an accurate measure of obesity? Scientists and health experts are now challenging this traditional definition, calling for a more nuanced approach to diagnosis.
Recent discussions have emerged challenging the traditional reliance on BMI for diagnosing obesity, advocating for a more precise approach that considers individual health factors. A global commission of 56 medical experts, as reported by the Associated Press, proposes redefining obesity by introducing categories such as ‘clinical’ and ‘preclinical’ obesity.
This new framework emphasises assessing fat distribution and its impact on organ function and daily life, moving beyond the limitations of BMI. Similarly, health experts are advocating for the adoption of the Body Roundness Index (BRI), which measures central obesity and abdominal fat using height and waist circumference, providing a more accurate assessment of health risks like Type 2 diabetes and heart disease.
BMI has long been criticised for its inability to distinguish between muscle mass, fat distribution and overall body composition. For instance, athletes with high muscle mass often find themselves classified as overweight or obese despite having low body fat. Similarly, individuals with a normal BMI can still have excessive visceral fat, putting them at risk for serious health conditions.
The U.S. Centres for Disease Control and Prevention (CDC) describes BMI as a ‘screening tool’ rather than a diagnostic measure. This means that while BMI can indicate potential weight-related health risks, it should not be the sole determinant of obesity. Instead, experts are advocating for a broader approach that includes waist circumference, metabolic health, and body fat percentage.
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Globally, obesity rates have surged over the past few decades. The World Health Organization (WHO) reports that worldwide obesity has nearly tripled since 1975, with over 1 billion people classified as obese in 2022. In the United States, nearly 42 per cent of adults are obese, raising concerns about related chronic diseases such as diabetes and cardiovascular conditions.
In Kenya, the 2022 Kenya Demographic and Health Survey (KDHS) revealed alarming trends: 45 per cent of women aged 20–49 and 19 per cent of men in the same age group are either overweight or obese. Urban areas and higher-income groups show even higher prevalence, reflecting changes in lifestyle, diet and reduced physical activity. Unlike in Western countries where obesity has been a longstanding issue, Kenya faces a double burden of malnutrition, with rising obesity rates alongside persistent undernutrition.
Recognising the shortcomings of BMI, a group of global health experts is pushing for a redefined diagnosis of obesity. Instead of relying solely on BMI, they propose a more holistic approach that includes waist-to-hip ratio, body fat percentage, and metabolic health indicators such as insulin resistance and high blood pressure. By integrating these new measures, healthcare providers can offer more personalised and effective treatments, addressing the rising prevalence of obesity-related health issues both locally and globally.
Obesity is a complex condition influenced by genetics, environment and lifestyle. The push to redefine how we diagnose it is a step toward better health outcomes.
In Kenya, where obesity is on the rise, adopting a more comprehensive approach could help individuals receive proper guidance and medical support.
Globally, this shift can ensure that obesity treatment is not just about numbers on a scale, but about overall health and well-being.
The conversation around obesity is evolving. The question is: Are we ready to change how we see it?
