Speaker 1: Already and this is this is the Daily Off.
Speaker 2: This is the Daily OS.
Speaker 1: Oh, now it makes sense. Good morning and welcome to
Speaker 1: the Daily OS. It's Friday, the twenty fourth of January.
Speaker 1: I'm Sam, I'm Zara. This week, a group of researchers
Speaker 1: have called for doctors to stop using the body mass index,
Speaker 1: or BMI to define obesity. It's a measurement system that's
Speaker 1: been around since the eighteen thirties, but now experts say
Speaker 1: it might be doing more harm than good. Today we're
Speaker 1: going to break down why this matters and what could
Speaker 1: replace it.
Speaker 2: Sam, this is such an interesting topic and one people
Speaker 2: have very firm opinions on. But I think that before
Speaker 2: we get to I guess this latest news and how
Speaker 2: people are feeling about it, I do just want to
Speaker 2: start at the beginning, and I think a good place
Speaker 2: to start is by defining what exactly BMI is. It's
Speaker 2: one of those things that we throw around as an
Speaker 2: acron but perhaps don't think about very often. And also
Speaker 2: how BMI calculates obesity, what goes into it.
Speaker 1: So it's basically a mathematical formula that takes into account
Speaker 1: your height and weight and gives you a weight range
Speaker 1: and a scale that shows whether you're underweight in the
Speaker 1: target range or overweight. And it was developed in the
Speaker 1: eighteen thirties. It's a very long time, very long time
Speaker 1: ago by a mathematician who was trying to find what
Speaker 1: he called the average male body. So as we were
Speaker 1: learning more about medicine in eighteen thirties, there was only
Speaker 1: about men only, of course, Yeah, then there was this
Speaker 1: drive to figure out a metric that took into account
Speaker 1: more than one measurement. And so even today, what's considered
Speaker 1: a normal BMI is between eighteen point five and twenty five.
Speaker 1: A person with a BMI between twenty five and thirty
Speaker 1: is considered overweight, and a person with a BMI over
Speaker 1: thirty is considered obese. A person is considered underweight if
Speaker 1: the BMI is less than eighteen point five. But here's
Speaker 1: where it all gets a little potentially problematic. Experts say
Speaker 1: it's an incredibly simplified way of looking at health. So
Speaker 1: the Butterfly Foundation, for example, which is Australia's national eating
Speaker 1: disorder charity, has called it outdated because it doesn't take
Speaker 1: into account things like muscle mass, bone structure, age, sex
Speaker 1: or ethnicity.
Speaker 2: I mean, it's incredible when you think about all the
Speaker 2: advancements we've had in so many areas of health. The
Speaker 2: fact that we are using a metric that was conceived of,
Speaker 2: you know, in the eighteen hundreds is fascinating. There was
Speaker 2: a study this week that called into question whether BMI
Speaker 2: is actually the best way to define obesity. Talk to
Speaker 2: me about what they actually found in that study.
Speaker 1: So this study was a cumbination of a number of
Speaker 1: different streams of research, and in twenty twenty two researchers
Speaker 1: essentially made a commission where they were attempting to bring
Speaker 1: together all of these findings to almost once and for all,
Speaker 1: workout whether BMI is the right way to be measuring obesity.
Speaker 1: They had fifty six leading experts in this from different countries,
Speaker 1: and what they found is pretty striking. So they found
Speaker 1: that under the current BMI system, someone might be classified
Speaker 1: as obese but show no evidence of health problems or
Speaker 1: limitations in their daily activities. And on the flip side,
Speaker 1: somebody might develop obesit related diseases without technically being classified
Speaker 1: as obese under the BMI structure. And if you expand
Speaker 1: it beyond that study and look at an analysis from
Speaker 1: other sources over the years, including Harvard University has done
Speaker 1: a lot of work in this space. Then other issues erase.
Speaker 1: You know the fact that a BMI calculation doesn't take
Speaker 1: into account whether you're pregnant an athlete with large muscle mass,
Speaker 1: and that historic calculations were not only, as you said before,
Speaker 1: based on the male, the average male, but the average
Speaker 1: white male. And now we know that body composition can
Speaker 1: vary a lot by race and ethnic group. So I
Speaker 1: guess if you were to bundle up these findings, really simply,
Speaker 1: it's taking something very complex and trying to make it
Speaker 1: simple but potentially failing.
Speaker 2: Okay, So there has been recognition that perhaps the system
Speaker 2: that we've been using for hundreds of years is falling
Speaker 2: short at the moment, and that it is oversimplifying a
Speaker 2: complex matter, as you said, But there needs to be
Speaker 2: some sort of indication as to how somebody's health is faring.
Speaker 2: What are these researchers proposing could be in place of BMI,
Speaker 2: for example, So.
Speaker 1: They haven't agreed upon what measurements specifically should be taken
Speaker 1: to define obesity. You know, whether it's waste measurements, bone density,
Speaker 1: body fat percentage, height, weight, multiples of that, etc. But
Speaker 1: what they have said with some clarity is the definitions
Speaker 1: of obesity, and they've got two different definitions. They've got
Speaker 1: pre clinical obesity and clinical obesity.
Speaker 2: And sorry, so to clarify, that's because the current definition
Speaker 2: is so closely linked to BMI exactly. Okay, So they're
Speaker 2: separating this and they want new definitions of how someone
Speaker 2: can be classified as obese.
Speaker 1: Yeah, and they've kind of done away with the term
Speaker 1: overweight as well, so they're replacing it with this term
Speaker 1: pre clinical obesity and that would be considered a risk
Speaker 1: factor for diseases. Clinical obesity would be treated as a
Speaker 1: standalone illness caused by how body fat affects organs and tissues.
Speaker 1: And so instead of just using BMI, they want doctors
Speaker 1: to be looking at a whole range of measurements, things
Speaker 1: like waste circumference, actual body fat measurements, or something called
Speaker 1: the waste to height ratio. They don't have clarity on
Speaker 1: which one should be the universally recognized measurement. Essentially, it's
Speaker 1: about having as many measurements as possible and as many
Speaker 1: indicators as possible.
Speaker 2: And I guess the issue that lies with that is
Speaker 2: that with BMI, there is an agreed upon universal way
Speaker 2: of measuring this, and it's accessible, it's understands, super easy,
Speaker 2: and it's easy. But I guess that's one of the shortfalls.
Speaker 2: But there's no consensus on what replaces it. So where
Speaker 2: does that leave us? Where does that leave health practitioners?
Speaker 1: Well, I think the research recognized that convenience is a
Speaker 1: large part of why BMI is so popular. If you
Speaker 1: google BMR calculator, you're given hundreds of different calculators which
Speaker 1: all get the same inputs, and they're very easy to
Speaker 1: measure inputs weight and height, that kind of thing. But
Speaker 1: it does lack the nuance that they're looking for here,
Speaker 1: And it's really important because the output of all of
Speaker 1: this is that some people might be getting unnecessarily limited
Speaker 1: in their access to certain kinds of healthcare, while others
Speaker 1: might have their real health issues overlooked. So let's say
Speaker 1: that there's an insurance company that offers a particular type
Speaker 1: of cover to those who, by the BMI standards, are
Speaker 1: classified as obese. There might be somebody who doesn't fit
Speaker 1: that BMI classification, who misses out on particular coverage, even
Speaker 1: though by other measurements they've got obesity related health issues.
Speaker 2: So you just touched on the way in which definitions
Speaker 2: of obesity can touch other areas of society, as you said,
Speaker 2: like private health insurance, but also I guess policy and
Speaker 2: data collection and all of that. So can you just
Speaker 2: talk to me about what would happen if the definition
Speaker 2: were to change and if the metric of obesity were
Speaker 2: to change.
Speaker 1: Yeah, you're right. I mean there's major funding decisions being
Speaker 1: made on how we understand the demographic makeup of Australa
Speaker 1: and what percentage of Australia would be classified as obese.
Speaker 1: It's a really interesting question. As I was looking into
Speaker 1: both health insurance companies and government policy, what I actually
Speaker 1: found was right now, they're not that reliant on BMI,
Speaker 1: and it made me think that maybe we're stuck in
Speaker 1: a bit of a transition zone anyway, and this research
Speaker 1: kind of affirms that. So most private health companies have
Speaker 1: their own BMR calculators, they do their own BMI calculations
Speaker 1: when you're asked to put in your weight and height
Speaker 1: when you register for health insurance, and they're all caught
Speaker 1: in that tension, I think. So I looked at Booper,
Speaker 1: for example, they've got their BMR calculator on the same
Speaker 1: page as an article about the problems of BMI calculations,
Speaker 1: and then you go to a government level and look
Speaker 1: at policy. I was reading the Australian government's National Obesity Strategy,
Speaker 1: which was made in twenty twenty two. It's a ten
Speaker 1: year strategy. In the eighty four page document, BMI is
Speaker 1: only mentioned once, and it's only mentioned once in a
Speaker 1: list of resources that could be offered to the general
Speaker 1: public as an easy way to track health. So a
Speaker 1: change in the wide scale use of BEMI potentially wouldn't
Speaker 1: have that much of an impact on the way our health,
Speaker 1: insurance or government policy systems work. I think it would
Speaker 1: more in the way that we talk about this topic.
Speaker 2: Keen to understand how the health care industry or community
Speaker 2: has responded to this. What have we heard so.
Speaker 1: Dieticians Australia came out strongly in support of the research.
Speaker 1: This week, their president, doctor Fiona Willer, made an interesting
Speaker 1: point about how people in larger bodies often have their
Speaker 1: health concerns either ignored or automatically blamed on their ways,
Speaker 1: and so they're particularly supportive of moving to what they
Speaker 1: call a more modern approach that brings in those factors
Speaker 1: that we've talked about.
Speaker 2: Okay, so this big body of research has been released,
Speaker 2: It's established that there is an issue with the way
Speaker 2: that we are at the moment both measuring and defining obesity.
Speaker 2: It has put forward some suggestions about changing the way
Speaker 2: that this is defined, but hasn't got any I guess
Speaker 2: agreed upon all universal ways to change that metric of
Speaker 2: be and I where does that leave us?
Speaker 1: So I think what the researchers say is the next
Speaker 1: step is to actually implement more complex definitions of obesity
Speaker 1: on top of the research we've already got. And what
Speaker 1: they're trying to get to there is what percentage of
Speaker 1: the population of whichever country they're operating in is actually
Speaker 1: obese by a more nuanced, complex, medically accurate standard. Once
Speaker 1: they have that data that gives a more accurate portrait
Speaker 1: of how the population is health wise, that's when they
Speaker 1: want to then do further research into other options for
Speaker 1: measurement that are available. I have to say that this
Speaker 1: next part of the project, I think for them, is
Speaker 1: going to be complicated because how do you bring in
Speaker 1: other factors of health amongst a population that's already been
Speaker 1: told they are obese or not. It's going to take
Speaker 1: a lot of you know, closed experimentation on working out
Speaker 1: health outcomes and whether there's a particular pattern in people
Speaker 1: who have a certain type of heart disease and whether
Speaker 1: that was related to one measure of obesity that was
Speaker 1: available and not used. It's complicated, and that's why I
Speaker 1: think it's taken forty eight bodies from forty eight different
Speaker 1: organizations to come together for this sort of research. But
Speaker 1: I do think that the overarching theme of all of
Speaker 1: this in terms of the next steps is a broader
Speaker 1: change in how we all think about obesity. And the
Speaker 1: goal that they have set for us is to move
Speaker 1: away from a one size fits all approach. And that's yeah,
Speaker 1: as I said, already happening on a government policy level,
Speaker 1: but we all need to be thinking about how to
Speaker 1: represent a more complex picture of human health.
Speaker 2: And of course we're talking about obesity today, but that
Speaker 2: same kind of nuance based evidence approach can be applied
Speaker 2: to all sorts of different health conditions across the spectrum.
Speaker 2: So Sam, thank you for taking us through that and
Speaker 2: for explaining more on this really significant research. Thanks Sarah,
Speaker 2: thank you for joining us for another episode of The
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