Obesity, a condition affecting over 1 billion people worldwide, is at the centre of a global health crisis.
In South Africa, the numbers are staggering, with projections forecasting obesity rates to rise by 47.7% in women and 23.3% in men by 2025.
This increase worsens the prevalence of non-communicable diseases (NCDs) like Type 2 diabetes, hypertension and cardiovascular diseases, which are among the leading causes of death in the country.
Despite its critical impact on health, the way obesity is diagnosed has long been debated. The traditional reliance on Body Mass Index (BMI), a simple measure of weight relative to height, has increasingly come under scrutiny for being too narrow and imprecise.
Now, a group of global experts are proposing a new approach to defining and diagnosing obesity, moving beyond BMI and introducing a more nuanced classification system.
The limitations of BMI
For decades, BMI has been the go-to measure for diagnosing obesity. However, it is far from perfect.
BMI does not differentiate between fat mass and muscle mass, meaning someone with high muscle mass, such as an athlete, could be misclassified as obese.
Conversely, individuals with excess body fat but a "normal" BMI might go undiagnosed.
Dr David Cummings, an obesity expert at the University of Washington and a co-author of the new report published in “The Lancet Diabetes & Endocrinology”, explained: “BMI is a risk factor and it may be one of the measures we use but it’s not the be-all and end-all.”
The report proposes a more comprehensive approach, combining waist circumference and other markers like waist-to-hip ratios with evidence of health problems directly linked to excess body fat.
This shift aims to better identify people who truly need medical intervention.
Under the new system, obesity would be divided into two categories:
- Clinical obesity: This applies to individuals who meet BMI and other diagnostic markers and show evidence of health problems caused by excess weight. These could include heart disease, high blood pressure, liver disease or chronic joint pain.
- Pre-clinical obesity: This includes individuals at risk of developing obesity-related health issues but who do not yet show symptoms of ongoing illness.
The goal of this new framework is to focus on patients who require immediate and targeted treatment while encouraging early intervention for those at risk.
South Africa has one of the highest obesity rates in sub-Saharan Africa, with women disproportionately affected.
In a previous interview with “Independent Media Lifestyle”, Dr Sindeep Bhana, the head of endocrinology at Chris Hani Baragwanath Academic Hospital, said that obesity in South Africa has serious consequences.
“We know that obesity leads to hypertension, Type 2 diabetes, cholesterol, sleep apnea, fertility problems and mechanical issues like lower back and joint pain. There are over 229 medical conditions directly linked to being overweight or obese.”
Meanwhile, one of the challenges in tackling obesity is the stigma associated with it. A study involving over 2.4 million obese individuals across seven countries revealed that many people feel uncomfortable discussing their weight with healthcare providers.
Bhana highlighted that it often takes up to six years for patients to receive proper medical assistance after seeking help, a delay that can worsen health outcomes.
Although the suggested classification modifications appear promising, they offer logistical obstacles. Accurately measuring waist circumference, for example, requires standardised techniques and tools that are not always readily available in clinics.
Differentiating between clinical and pre-clinical obesity involves extensive laboratory tests and health assessments as well as significant investment in healthcare professional training and diagnostic equipment upgrades - a job that could be both expensive and time-consuming.
Dr Katherine Saunders, an obesity expert at Weill Cornell Medicine, pointed out: “For a new classification system to be widely adopted, it would need to be extremely quick, inexpensive, and reliable.”
One of the most groundbreaking aspects of the report is its stance on obesity as a disease. The report challenges the binary debate over whether obesity is always or never a disease, arguing instead for a more nuanced perspective.
Professor Francesco Rubino, chair of the Global Commission on Clinical Obesity, stated: “Evidence shows a more nuanced reality. Obesity is not always a disease but in many cases, it is.”
This shift could change how obesity is viewed, moving away from stigmatisation and toward recognition as a complex health condition requiring individualised care.
The new definitions for obesity have been endorsed by over 75 medical organisations worldwide, signalling a growing consensus for change.
However, widespread adoption will take time, especially in countries like South Africa, where public health resources are limited.
As Cummings noted, the new system isn’t about drastically changing the percentage of people diagnosed with obesity but about better identifying those who truly need help.
This precision could be a game-changer in the fight against obesity, especially in a country grappling with its rising prevalence.