Local health experts are reconsidering their approach to obesity as new research criticises doctors’ reliance on the body mass index.
The paper, published in prestigious medical journal The Lancet, said the typical approach to diagnosing obesity was ineffective and prone to misdiagnosis.
Researchers criticised the definition of obesity being tied to BMI – a measurement of height and weight – as opposed to more accurate measurements of a person’s fat, muscle, and bone mass.
“BMI was never really designed to diagnose an individual’s health status, it was really developed to help us monitor big changes across population groups,” Massey University Māori Health and Nutrition professor Lisa Te Morenga told RNZ.
Experts say the current approach is too reliant on the Body Mass Index. (Source: 1News)
“It is a crude measurement. It’s excellent in large population studies because it’s cheap and easy to do… But if your doctor’s really just measuring your height and weight, they’re missing the whole picture.”
A diversity of body shapes and levels of fitness meant BMI wasn’t always reliable.
“Someone with a high BMI could actually have lots of muscle and be at a low risk of the clinical manifestations of obesity,” Te Morenga said.
“[Meanwhile] someone who has a relatively low BMI might be carrying a bit of fat around the organs which is actually high risk for some diseases associated with being obese.”
The report also suggested dividing obesity into two categories, ‘clinical’ and ‘pre-clinical’ denoting whether a person’s organ function had been impacted by excess body fat.
“This nuanced approach to obesity will enable evidence-based and personalised approaches to prevention, management and treatment… This will also save healthcare resources by reducing the rate of overdiagnosis and unnecessary treatment,” one of the key authors – Sydney-based paediatrician Louise Baur – said in a statement.
But Dr Wayne Cutfield, a professor of Paediatric Endocrinology at the University of Auckland’s Liggins Institute, criticised this approach.
“I think what they’ve inadvertently done is create a bit of an illusion that if you are obese but don’t have any associated diseases that you’re absolutely fine… But we know these diseases take years if not decades to develop, so you may not necessarily have these diseases right now but you could be well on the way to developing them,” he said.
“The article kind of focuses more on ‘clinical’ obesity and it creates an illusion that active management of ‘pre-clinical’ obesity isn’t really necessary. It is necessary.”
While those with a high BMI could remain healthy, Te Morenga said obesity was a constant health risk.
“There are groups that say you can be obese but healthy and that is true, but we’re talking about risk, and having obesity does confer more risk,” she said.
The takeaway, she said, was that obesity could look different for different people.
“I think this is a good reminder for our GPs to investigate obesity a little bit further with their patients. Don’t take for granted that someone who looks a normal weight isn’t storing fat in a way that might put them at risk.”
rnz.co.nz
