The Current - Understanding obesity, beyond BMI

Episode Date: January 17, 2025

Doctors are proposing a new definition of obesity that goes beyond measuring BMI. We talk to Dr. Sanjeev Sockalingam about how the new diagnosis, and drugs like Ozempic, could change the conversation around body size and health.

Viking. Committed to exploring the world in comfort. Journey through the heart of Europe on a Viking longship with thoughtful service and cultural enrichment on board and on shore. Learn more at Viking.com. This is a CBC Podcast. Hello, I'm Matt Galloway and this is The Current Podcast. When you go for a checkup, your doctor might measure your height and your weight. That may lead to a conversation about obesity. But a new report published in The Lancet says the diagnosis is actually not that simple. Dr. Katherine Morrison from McMaster University in Hamilton, Ontario is a member of the Commission

on Clinical Obesity which published that report. Traditionally, we've defined obesity on the basis of body mass index, which is a weight for height measure. And many folks have noted that this is really not a useful individual measure that helps us define health in our patients. The commission recommends a new way of thinking about the ties between obesity and health, one it believes will improve the lives of those living with this condition. Dr. Sanjeev Sokhalingam is the scientific director

at obesity Canada, as well as the chief medical officer at CAMH, the centre for addiction and mental health. And he's with me in studio now. Good morning. Good morning, Matt. Just to understand these recommendations, I want to talk about what they're going to mean in a moment,

but pick up a little bit on what Dr. Morrison was saying there. Around the traditional way of, of, of diagnosing what they're going to mean in a moment, but pick up a little bit on what Dr. Morrison was saying there. Well. Around the traditional way of diagnosing obesity using BMI, the body mass index, what's wrong with that? Well, the body mass index is one, it's convenient, it's been around for a while, but its roots are actually from insurance databases that try to predict health risk and those databases were predominantly involving European men. So lacking diversity in the samples and populations

and were never actually first intended to be using clinical practice. They're actually used at a population level. So thousands of people, but because of the ease and some of the risk and associations with health outcomes that started to emerge over time, it has been because of the ease and some of the risk and associations with health outcomes that start to emerge over time, it has been one of the easiest widely implemented measures to start to define

this entity that we call obesity. Height and weight, essentially. Height and weight. And so what's the better way of doing this? Well, I think we've recognized, and even if you look at any of the treatments that we have for obesity right now and how they've emerged, they still use body mass index as one of the criteria. What we see in the Lancet Commission and our current guidelines is that body mass index is

accepted as a screening tool, but not the be-all and end end all of assessing obesity. And obesity is quite complex. And so there are other measures like waist circumference, height to waist circumference, and even some imaging that might look at actual fat tissue distribution in the body. Now, all of these are great in principle, but we know that in a busy family physician's practice. It sounds like they take more time than standing somebody on a scale and getting a tape measure. Absolutely. So these are the questions that happen. It's great that we're challenging BMI because of its roots and some of its limitations. And it doesn't capture the individual patient who's living with obesity, which is much more complex. Not every patient who's living with obesity with a body mass index of say 35 is quite comparable. They all each have individual health conditions, organ dysfunction and impacts

on quality of life. This is why the definition in some ways of obesity is being pulled apart. As I understand it, what they're looking at doing is saying that people who have a BMI over 25 looking at doing is saying that people who have a BMI over 25 and too much fat in that con, in that, in that conversation, um, but they're otherwise healthy, that you kind of leave them alone. Um, that you keep an eye on them, but you don't do anything as an intervention. And that's called preclinical obesity. But then there is something beyond that, which would be clinical obesity. How do you understand those two definitions? Well, I think as a profession and someone who works across multiple fields, including obesity, our field is trying to grapple with this because, you know,

this was a consensus, an international consensus. It's not a guideline and it's not based on evidence, but our current guidelines, I'll just maybe Matt, just to highlight our current guidelines define in Canada, obesity as a chronic disease that impacts health, increases future kind of health risk, and has impairment to the individual. What this is new paradigm of preclinical and clinical is saying we will use more measures

in body mass index, which I think we all agree with that we need to do, and we will look at measures of organ dysfunction related to fat tissue. So if you have excess fat in your liver, your lungs, et cetera, you may have symptoms, shortness of breath, you may have other symptoms related to that, and that would move you into clinical. But if you don't have those symptoms, you're not yet at that threshold.

That's right. And you may not get to that threshold. Right. That is correct. Is that? That is correct. Okay. That is correct.

So there is debate in the field right now about do we have enough metrics or measures to actually start to define pre-clinical. At what point we know that excess fat tissue can be measured in some ways in symptoms, but sometimes there are early effects that are not measured by symptoms and signs as well. If you do this, what difference is that going to make for people who are living with obesity? There's a nuance to the conversation, I think, that's being added that perhaps wasn't there before. So I think the Lancet Commission's work has had a few messages that are building on our existing evidence guidelines

and understanding of obesity. So one is BMI is a limitation. So I think that's what we're seeing from the Lancet Commission, and we need to look at more measures to do that. Number two is, which I think is really important, that we need to personalize care for people with obesity. What does that mean?

So an individual living with BMI and additional measures that may look at organ dysfunction or excess weight or fat tissue, excuse me, may end up having diabetes or other health conditions, arthritis that limits their care. So we need to look at what those factors are and then match the treatment that they need and the intensity of treatment for them, which isn't, you know,

psychological or behavioral medications. And we have metabolic and bariatric surgery. So that's the third thing. The fourth would be the impact is they do talk about something that's really critical, which is people living with obesity in 2025 still endure significant stigma, even though we accepted by all medical associations in North America that obesity is a chronic disease over a decade ago. And so what that means is we need to think about how do we create environments,

we teach individuals and healthcare providers importantly, who are probably the ones who carry a significant bias about what obesity is, that obesity is not about eating less and moving more, that it is a chronic disease. There are ways to measure it and there are treatments available. Do you believe that we are in an obesity epidemic? This is a word that's applied right now, and it can be childhood obesity, but more broadly as well. And that's why there is urgency in some ways,

people say, to understanding these new definitions. Do you believe that that's the case? Well, we've seen an increase over time in the overall prevalence of obesity, and especially in children and youth, there are multiple factors for this. I always hear the terms epidemic, crisis. I think these are ways in which we use language

to promote and increase our awareness and understanding of obesity and to get policy changes that we deeply need to try to increase access and better care for patients. So are we in a epidemic? I think I would frame it this way. I think one in three, approximately one in three Canadians are living with obesity right now.

That sounds serious. That's pretty significant. We know that obesity has a myriad of impacts on our functioning and life for many Canadians. It costs $27 billion of indirect and direct costs for not treating obesity in some recent studies, including some from Obesity Canada. And we know that it impacts the quality of life,

functioning, and importantly, the mental health. And that's probably my interface here is that there's a significant kind of impact on people's wellbeing, mental health and mental illness as a result of this. That speaks to the stigma issue as well. And you said something really interesting in talking about the stigma, that it's physicians that carry a lot of that stigma. What has to change, I mean if there's debate around these new definitions but also the new way of measuring obesity, what has to change to address that stigma that perhaps might be carried by physicians,

but would be felt by people living with obesity? I think one is first we have to continue to do research and have the evidence about how we're defining and implementing these measures for assessing and defining obesity. I think if we continue to debate, uh, it causes a little bit of confusion. Is there reluctance to thinking differently about obesity and what you said was it's not about eating less, it's not about moving more,

but is there a reluctance within some corners of the medical community to rethink that? I think, well, remember, uh, again, I'm not that old, but I know many individuals, including myself, did not learn about obesity in my medical school training at all. It was more the complications of weight that we talk about. And this notion of stigma, how we measure obesity,

some of the pathophysiology or the causes of obesity weren't really explicitly in our curriculum when we were training. And so one of the things I would argue is we have to retrain our current workforce about understanding obesity. I think simplifying our definition and really building on what this Lancet Commission talked about and having further discussions important. But I also think it starts with just having people

living with obesity, really telling their story, being part of these training. We have at Obesity Canada, a competency framework, training framework that people living with obesity and healthcare providers co-created. And those kinds of things can be helpful to start changing how we train in our current and new medical schools people who are caring for individuals living with obesity

and think about how they can be better educated with these new frameworks and paradigms. Just in the last couple of minutes, it's interesting, we're having this conversation at a time when there are drugs that are wildly popular that many people are taking to help treat obesity. These drugs are really expensive. The suggestion is that perhaps these new definitions could restrict access to those drugs for those who are not at pre-clinical obesity, but to those who are in that definition of clinical obesity. How do you think the drug conversation

will impact what we're talking about now? Well, I think this is part of the debate about preclinical and clinical obesity. I think the Lancet Commission really focused on biological outcomes and they talk about organ dysfunction and the impact of obese or excess fat tissue. I think where they have not really captured is people's lived experience living with obesity, right? There's nothing mentioned about quality of life, the impairment in some of the social

factors work, mental health, for example. All of which are being addressed by these drugs, and people will say. That's right, right. And so one of the things, you know, through our Canadian obesity guidelines, we chose not to go into clinical preclinical deliberately. I think we took an approach when we developed those guidelines to say, we're looking at health outcomes and functioning and the impact of excess fat on all of these measures.

But we're also doing it in a shared model with the people living with obesity. Cause someone might say to me, the most important thing for me is to be able to lose weight so I can move more to be functioning and be out with my children, for example. That's not really captured in an organ dysfunction kind of dialogue and the clinical and preclinical

obesity, it is indirectly perhaps. Um, and so these are the things where we need to think about what are we using treatments that are evidence-based for? How can we increase access for those who are really having functional impairment and how we define it and making sure we're not making the mistake of make defining that from purely a

physician or healthcare provider standpoint. The complexity in this issue is what makes it so fascinating. Um, really appreciate you being here to talk more about this and we will certainly come back to it again. Thank you. Thank you, Matt.

Dr. Sanjeev Sokhalingam is the scientific director at Obesity Canada.