Could a new definition change the way we think about obesity?

A new proposal to radically overhaul the way obesity is diagnosed may have “profound ramifications” for people’s access to healthcare, treatment and the existence of widespread weight-related social stigma.

The commission comprising 58 international and Australian experts, published their proposal in The Lancet Diabetes & Endocrinology on Wednesday. They are calling for greater nuance in diagnosis and going beyond body mass index (BMI) to define when obesity is a disease.

Obesity was first recognised as a disease by WHO in 1948, yet this classification remains highly controversial even within the healthcare industry.

BMI tells us nothing about a person’s health, experts say.Credit: Getty Images

The issue is that obesity is a spectrum. Some people with excess body fat can remain in good health, while others with excess body fat experience impaired organ function, including their heart, joints, kidneys or liver.

A blanket diagnosis of obesity as a disease, the panel argues, is therefore not only inaccurate but poses a risk of overdiagnosis, resulting in unwarranted use of drugs, technologies and surgical procedures.

“And if we underdiagnose it in others, then people who may benefit from treatment of obesity may miss out in receiving effective therapies,” says panel member and former president of the World Obesity Federation, Professor Louise Baur.

To address this, the commission recommends a new approach recognising two categories of obesity: clinical obesity and also preclinical obesity.

“The former is a disease that warrants treatment,” says Baur, of the University of Sydney.

Clinical obesity is a chronic illness where excess body fat causes reduced organ function or significantly reduced ability to conduct day-to-day activities, such as bathing, dressing, eating and continence.

“Preclinical obesity is when you have a high body fat but no associated health problems,” says Baur.

Currently, obesity is defined as having a BMI greater than 30 – or 27.5 for Asian populations. BMI does not tell us about the health of an individual and can be high, not just because of excess fat, but as a result of strong muscle mass or bone mass.

“It doesn’t tell us how well our organs are working,” says commission chair Professor Francesco Rubino of King’s College London.

Evaluating obesity, therefore, should include BMI plus at least one measurement of body size, such as waist circumference, waist-to-hip ratio or waist-to-height ratio.

If obesity is confirmed, people should then be assessed for possible clinical obesity based on findings from medical history, physical examination, and standard laboratory tests.

Healthy people can still experience weight stigma in healthcare settings.Credit: Getty Images

Over 1 billion people in the world are now estimated to be living with obesity, including about a third of Australian adults – or 6.3 million people.

Many of those people experience weight stigma in both social and healthcare settings, largely because of the misconception that obesity is caused by factors solely within their control.

Individuals enduring weight stigma or discrimination around the world have a 60 per cent greater risk of mortality and are two and a half times more likely to experience mental health disorders.

“They are shamed and blamed and have largely been ignored in terms of therapeutic interventions,” says Professor John Dixon of the Iverson Health Innovation Research Institute, Swinburne University of Technology. “And they don’t seek care because they feel they are to blame.”

Yet, the science shows that genetics and a person’s environment are largely to blame, Dixon adds: “Those two things, they had no choice in.”

The commission hopes that the new classification will help decrease stigma towards people in larger bodies.

“Weight bias is stronger in people who think obesity is easily reversed by just deciding to eat less and exercise more,” says Rubino. “If you think obesity is an illness, it’s easier for people to appreciate it’s more complex than that.”

He uses the analogy of cancer: “Even when we think it’s associated with lifestyle, like smoking, we don’t think it’s enough to stop smoking to cure a cancer because we appreciate… it needs medical attention.”

Until now, the inability to recognise obesity as a direct cause of ill health has undermined effective treatment, the panel states.

For treatment to be covered by health insurance, for instance, it typically requires the presence of another disease, such as diabetes.

“Such practices can effectively and unfairly deny access to care among many people who already have objectively ill health due to obesity alone,” the panel explains.

They recommend those diagnosed with clinical obesity should receive evidence-based treatment aimed at improving the body functions impaired by excess body fat rather than solely losing weight. Treatments should include access to lifestyle support, medication and/or surgery.

Those living with pre-clinical obesity should receive health counselling and monitoring, as well as treatment if necessary, to reduce high levels of risk for future diseases.

‘This is a health condition’

Dr Terri-Lynne South, chair of Obesity Management at the Royal Australian College of General Practitioners, says the proposal is welcome.

“For people who do have the clinical definition of obesity, recognising it as a disease does give it legitimacy that this is a health condition, and it needs appropriate funding and evidence-based treatments,” she says.

“When we understand there is true path-physiology, it does reduce the stigma to say it is not the individuals’ fault. They did not choose the genetics that has put them at increased risk of developing this disease, and we need to treat it with respect.”

‘We need to address stigma among our healthcare practitioners’

Professor John Dixon

There are currently no PBS-listed medications for obesity, limited public funding for bariatric surgery, and just five allied health visits that a patient can access under a GP management plan.

“It is not enough for this type of very complex and chronic condition,” says South, who was not involved with the commission.

The commission members say the next steps will involve discussions with policymakers and healthcare providers.

However, they acknowledge that change may be a slow process as most practitioners still don’t treat obesity as a disease and still believe it is the person’s fault, admits Professor John Dixon.

“We need to address stigma among our healthcare practitioners,” he says. “We’re going to have to do a lot of work in Australia to change those views.”

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