Key points
- Researchers introduce a new concept of preclinical obesity
- They claim BMI poorly reflects body fat level
- Experts want to split cases of obesity into preclinical and clinical
- New definitions already welcomed by 76 health organisations globally
ISLAMABAD: Rethinking the way people define obesity could help millions of people worldwide, claims a group of researchers who are trying to introduce a novel category of “preclinical” obesity.
According to New Scientist, currently, the World Health Organization (WHO) defines obesity as having extra body fat that poses a risk to health. It recommends that healthcare workers find out whether people are obese by calculating their body mass index (BMI) which is a measure of weight relative to height.
According to this definition, a BMI between 18.5 and 24.9 is healthy. However, below or above that category indicates someone is under or overweight.
A BMI above 30 shows that someone is obese.
High levels of body fat can indeed cause it to enter organs like the liver and pancreas, impairing their function.
Along with this, it can also lead to inflammation, increasing the risk of conditions like cancer, liver disease, and heart problems.
Inadequacy of BMI
However, BMI inadequately shows a person’s body fat levels. “With BMI, we don’t know if that ‘excess’ weight is due to excess body fat or stronger muscle mass or bone mass,” says Francesco Rubino at King’s College London, who spearheaded the review on obesity.
Body fat levels, even when measured correctly through assessing the waist or X-ray scans, don’t fully dictate someone’s health. “No two people respond the same way to excess body fat. This is impacted by a person’s race and ethnicity, their age, what foods they eat, and genetics plays a tremendous role,” says Steven Heymsfield at Louisiana State University.
Defining obesity
That is why Rubino and his colleagues want to split cases into preclinical and clinical.
Both forms would be characterised as having extra body fat, however, only the clinical form would include symptoms induced by excess fat, like breathing difficulties, heart problems, or difficulty carrying out daily activities.
Preclinical obesity, on the other hand, raises the risk of finally developing such obesity-related symptoms, says Rubino.
“This would be akin to how people can have prediabetes, where their blood sugar levels are higher than usual, but not high enough to be diagnosed with full-blown type 2 diabetes,” says Rubino.
“Under the proposed changes, healthcare staff would directly measure people’s body fat levels using waist width or X-rays in addition to calculating BMI, although someone with a BMI above 40 would always be assumed to have excess fat,”says Heymsfield.
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“They would then use blood tests to assess organ health and ask people whether they are experiencing symptoms. The blood tests are routinely done by many clinicians anyway, but the direct body fat measurements would somewhat increase their workload,” he further said.
Better advice
“If widely adopted by clinicians, the new definitions could mean people are offered advice and treatment that is better tailored to their bodies,” says Rubino.
He further added, “generally, those with preclinical obesity might only need to monitor their health and adopt lifestyle changes, while those with the clinical form are more likely to require treatment with drugs or surgery,” says Rubino.
“It would allow us to more appropriately triage people to the right care,” says Adrian Brown at University College London.
Laura Gray at the University of Sheffield appreciates the proposed changes. “It’s much needed. These guidelines set out for clinical practice what current research is saying,” she says. “Not everyone with obesity according to BMI is unwell, and not everyone with a lower BMI is healthy.”
It would allow us to more appropriately triage people to the right care” –
Adrian Brown at University College London.
These new definitions have already been accepted by 76 health organisations worldwide.
“The hope is that defining obesity in a more nuanced way shows it is a disease in its own right. It isn’t just a consequence of behavioural things, there’s lots of risk factors, environmental, psychological and genetic,” says Gray.
