TRANSCRIPT
Many of us have probably measured our B-M-I, or visited a G-P who has done so.
The body mass index figure, designed to measure an individual's body fat, comes from a *formula which generates a ratio of someone's weight to their height.
The Australian Institute of Health and Welfare says it doesn't measure the distribution of weight around their body, or describe the same degree of fatness in different individuals.
Now experts are raising questions around how accurate or helpful it is in determining an individual's health.
Queensland-based Sarah Cox says her doctor told her to lose weight because her body mass index, or B-M-I, was too high.
"I was enjoying life. The standard struggles with mental health that some people have, but I had no physical issues whatsoever. He started me on weight loss medication, quite strong weight loss medication. He immediately referred me to an exercise physiologist and a dietician.So that dietician put me on a very, very low calorie diet, which combined with the weight loss medication just basically sent me immediately into an eating disorder."
The 35-year-old says she was visiting a GP for a completely unrelated check-up following a procedure she had on her nose.
Instead, the GP asked her to stand on the scales and spoke for the majority of the appointment about how she needed to lose weight, despite the fact Sarah says she felt healthy.
Sarah says her doctor also failed to take any blood tests or measure her health in other ways before putting her on weight loss medication and referring her to a dietician.
It's this appointment in 2018 which Sarah says triggered her battle with anorexia nervosa for two-and-a-half years.
"So in actual fact, their plan which was done purely to reduce my BMI is what made me unhealthy is what made me sick is what started two and a half years of hospitalisations and almost losing my life was purely because a doctor thought it was appropriate to reduce my BMI despite everything else being healthy."
While the B-M-I has been used for more than 50 years by doctors as a measure of determining an individual's health, particularly in relation to weight gain and obesity, a group of experts from Australia and around the world are now questioning this reliance on the metric.
Professor John Dixon from Swinbourne University's Iverson Health Research Institute was one of the authors on the Lancet Institute report conducted by members of the Global Commission on Clinical Obesity.
So what exactly is B-M-I?
"BMI is simply our weight, our body weight corrected for our height. And it's actually a very good way of assessing body fat for the vast majority of people. But it doesn't tell us about where our fat is stored. It doesn't tell us about where our fat has gone to into ectopic organs, such as the liver, the pancreas, the heart, and it doesn't tell us anything about her illness associated with it."
An individual with a B-M-I over 30 is considered to be 'obese', which is typically deemed unhealthy.
But experts say a patient might fall under this range and experience a range of health issues, while another individual could be classified as obese and be generally healthy.
The report proposes the need for a clear distinction between pre-clinical and clinical obesity to determine tailored treatment for patients who may experience health issues as a result of obesity.
Professor Wendy Brown, chair of the department of surgery at Monash University, was also an author on the report.
"One is what we are saying is preclinical obesity, and these are people who are carrying extra fat, extra fatty tissue, but it's actually not impacting on their sense of wellbeing or their ability to function in society or their health at this time point. Then we have a definition called clinical obesity, and these are people who are carrying excess fat, and these are people where that excess fat is impacting the health, so they have developed a disease like diabetes, like heart disease, or it is impacting their sense of wellbeing."
The group of 58 experts, including Professor Brown, are proposing the B-M-I is supplemented with other measurements to understand where weight is being carried, such as measuring around the waist or hips, as well as the use of X-rays and body composition measures.
"If you are an athlete and you weigh a hundred kilos and you're solid muscle, your BMI might flick up to 30, but you're obviously a really healthy person because you're lean and you're fit and you're active. But if your BMI is 30 and that's largely made up of fat, particularly if that fat's carried around the central area or around your heart, then that becomes an unhealthy situation."
The use of B-M-I is also restrictive when it comes to accessing mental health care.
Twenty-two year-old Varsha Yajman [[YAHJ-men]] confronted barriers to receiving adequate support for an eating disorder when she was 14 years old due to her GP's over-reliance on BMI.
She says it took three years before she received a diagnosis, despite initially visiting the doctor with her concerns on a regular monthly basis for around four months.
"My weight kept dropping, but the whole idea was, oh, just eat more and exercise less, and you'll be fine. There was no acknowledgement of the mental side of things. And then when it came to my BMI, it was around, oh, well, it's not severely low. That's okay. Or you're still within the range. And then when it was out of the range, it's not too bad still. So it kept coming into the question of how bad do I need to be? Or how sick do I need to be to actually have an eating disorder to actually get help?"
There are different BMI metrics that take into consideration age, gender and ethnicity.
But as an Indian-Australian woman, Ms Yajman still feels the model is problematic as its original metrics are based on a typical white European male.
"So when I went to the doctor, my doctor at the time was South Asian and I'm South Asian myself. So I thought there would be a bit more understanding. But then I think when you bring in the stigma of mental health as well into these sorts of conversations, it's easy to just say that, oh, well your BMI is fine, or you're not severely underweight, so you're fine. And I remember I'd obsessively go home and check BMI and say, oh, well if I'm this weight, then what does my BMI mean there? And I remember even conversations with friends. It would come up like, oh, my BMI is too high. And you just hear somebody say that."
Some experts say the different B-M-I cutoff points accounting for ethnicity are also flawed.
Dr Fiona Willer is an accredited practising dietician and lecturer in nutrition and dietetics at Queensland University of Technology.
"Not everyone is a thin white male. Wasn't then, isn't now. And so it essentially has put flaws into the system, but those flaws are on top of an already flawed measurement tool. The cutoff points themselves, I should add though, are essentially pretty arbitrary. They tend to be round numbers for ease, but bodies aren't made with round numbers in mind in terms of health risks. So there's flaws in using the BMI overall. And then there's flaws in where those cutoff points are determined."
Dr Willer says the use of B-M-I and weight measurement is especially problematic for people with eating disorders.
It's a tool that eating disorder charity the Butterfly Foundation has also previously described as an outdated measure.
"It means that it's a minefield for people with eating disorders which occur across the weight spectrum, but are often dismissed or in fact endorsed If they've got a larger body size and they've got a hugely problematic eating disorder and all of their health professionals and the people around them are commending them for their dieting efforts, meanwhile, they're extremely malnourished."
In fact, she thinks the B-M-I and labels of obesity should be avoided completely in general practice.
"It's a terrible tool and actually a lot of the time, larger body size can co-occur with all sorts of different things, but saying that A plus B equals C is not the same, the body weight is not necessarily the cause of it. We need to really get diagnoses that are based on the condition that the person has. They've got a sore knee, let's treat that knee as we would in a smaller body person, not send people away for weight loss advice rather than pain management, for example."
Fifty-six year-old Lexii Marquardt [[MAR-kwart]] has experienced shame related to her weight all her life.
"I've been considered overweight, obese, fat, chubby, and all the rest of the terms used since childhood. I think that it's certainly had a significant impact on my mental health. I do have, well, actually I've been diagnosed with bipolar disorder, but it manifested itself at a very young age with significant depressions."
Ms Marquardt says she played competitive tennis for over 40 years, and her body size hasn't affected her physical health.
She hopes the commission's proposed new definitions of obesity can help alleviate stigma for those with larger bodies.
"If that preclinical obesity diagnosis or category becomes relevant, then you may actually then stop a number of people who sit in that moving into the clinical obesity because they're not afraid to go and seek help, because they're not afraid of that judgement and the perceptions around somebody being in a larger body, somebody being overweight, whatever you want to call it."
Sarah also wants doctors to use other measures of health and thinks B-M-I should solely be used for measuring population health.
But she believes the obesity label should be scrapped altogether, so the focus can be on receiving safe and appropriate healthcare, regardless of body size.
"I can't see a purpose in a GP using the word obese. I think we need to stop looking at the number on the scale because it's not the measure of health. We need to look at what are the things that are actually being impacted. Are we looking at, someone has compromised respiratory function, they have compromised movement. Doctors need to listen to their patients. They need to stop coming in with a preconceived idea of what the conversation or what the appointment's going to look like, and they need to stop and listen to their patient and what their patient actually needs and wants from the appointment."
And if this story has raised issues for you or someone you know, you can get support from The Butterfly Foundation through 1800 33 46 73 - or via their website.
*BMI takes a person's weight in kilograms and divides it by the square of their height (their height multiplied by itself)
