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5th Canadian Obesity Summit – Four More Days To Submit Your Abstracts!

banff-springs-hotelEvery two years the Canadian Obesity Network holds its National Obesity Summit – the only national obesity meeting in Canada covering all aspects of obesity – from basic and population science to prevention and health promotion to clinical management and health policy.

Anyone who has been to one of the past four Summits has experienced the cross-disciplinary networking and breaking down of silos (the Network takes networking very seriously).

Of all the scientific meetings I go to around the world, none has quite the informal and personal feel of the Canadian Obesity Summit – despite all differences in interests and backgrounds, everyone who attends is part of the same community – working on different pieces of the puzzle that only makes sense when it all fits together in the end.

The 5th Canadian Obesity Summit will be held at the Banff Springs Hotel in Banff National Park, a UNESCO World Heritage Site, located in the heart of the Canadian Rockies (which in itself should make it worth attending the summit), April 25-29, 2017.

Yesterday, the call went out for abstracts and workshops – the latter an opportunity for a wide range of special interest groups to meet and discuss their findings (the last Summit featured over 20 separate workshops – perhaps a tad too many, which is why the program committee will be far more selective this time around).

So here is what the program committee is looking for:

  • Basic science – cellular, molecular, physiological or neuronal related aspects of obesity
  • Epidemiology – epidemiological techniques/methods to address obesity related questions in populations studies
  • Prevention of obesity and health promotion interventions – research targeting different populations, settings, and intervention levels (e.g. community-based, school, workplace, health systems, and policy)
  • Weight bias and weight-based discrimination – including prevalence studies as well as interventions to reduce weight bias and weight-based discrimination; both qualitative and quantitative studies
  • Pregnancy and maternal health – studies across clinical, health services and population health themes
  • Childhood and adolescent obesity – research conducted with children and or adolescents and reports on the correlates, causes and consequences of pediatric obesity as well as interventions for treatment and prevention.
  • Obesity in adults and older adults – prevalence studies and interventions to address obesity in these populations
  • Health services and policy research – reaserch addressing issues related to obesity management services which idenitfy the most effective ways to organize, manage, finance, and deliver high quality are, reduce medical errors or improve patient safety
  • Bariatric surgery – issues that are relevant to metabolic or weight loss surgery
  • Clinical management – clinical management of overweight and obesity across the life span (infants through to older adults) including interventions for prevention and treatment of obesity and weight-related comorbidities
  • Rehabilitation –  investigations that explore opportunities for engagement in meaningful and health-building occupations for people with obesity
  • Diversity – studies that are relevant to diverse or underrepresented populations
  • eHealth/mHealth – research that incorporates social media, internet and/or mobile devices in prevention and treatment
  • Cancer – research relevant to obesity and cancer

…..and of course anything else related to obesity.

Deadline for submission is October 24, 2016

To submit an abstract or workshop – click here

For more information on the 5th Canadian Obesity Summit – click here

For sponsorship opportunities – click here

Looking forward to seeing you in Banff next year!

Edmonton, AB


How Strong Is The Physiological Drive To Regain Lost Weight?

Yo-Yo Rubber Band Feb 2014It is now well established that the almost non-existant rates of long-term weight loss are not because of lack of will power or lack of motivation. Rather, they are firmly embedded in human (and animal) physiology, that is designed to defend body weight at all costs through complex neuroendocrine homeostatic mechanisms that will eventually wear out even the staunchest dieter.

But just how strong is the physiological drive to defend and regain lost body weight? Or even more specifically, how much does an increase in appetite counteract weight loss?

This is the topic of a paper by David Polidori and colleagues, prepublished on bioRxiv*.

The researchers use data from a 52-week trial of canagliflozin, a sodium glucose co-transporter (SGLT2) inhibitor leads to a urinary glucose loss of approximately 90 g/day throughout the duration of treatment.

This amounts to a net daily energy loss of ~360 kcal/day that occurs without directly altering central pathways controlling energy intake and without the patients being directly aware of the energy deficit.

Based on the observed changes in body weight over time, the researchers used a validated mathematical method to calculate changes in daily energy intake using principles from engineering control theory.

The complex mathematical formula takes into account a wide range of parameters including changes in the energy expenditure rate and density of fat and fat-free mass, energy cost of fat and protein turnover, dietary and adaptive thermogenesis as well as changes in physical activity (no change in physical activity was assumed in this study).

Subjects in the treatment arm showed the typical initial weight loss (of about 5 Kg) followed by the maintenance of a weight-loss plateau throughout the remainder of the study, a pattern which, in light of a continuing daily energy loss of about 360 kcal is consistent with a proportional feedback control system that serves to limit the amount of weight loss and creates a drive towards weight regain (think of this as the tension that counteracts a steady pull  on a rubber band).

Based on their calculations, the amount of daily increase in caloric intake required to maintain the weight loss plateau (rather than continuing to lose weight), was in the order of about 100 Kg/day per Kg weight loss. This is substantially more than the reduction in metabolic rate generally seen with weight loss (of about 10-20% of body weight) is only about 30 kcal/day per Kg weight loss).

When applying these finding to the typical weight-loss curve seen in the usual commercial weight loss programs (an initial weight loss followed by gradual weight regain), the researchers show that the difference between the homeostatic drive to eat and the actual energy intake, a quantitative index of the ongoing effort to sustain the intervention in the face of the continuing biological signals to overeat, requires that subjects have to demonstrate a persistent effort to avoid overeating above baseline during the intervention even when the average energy intake returns to near baseline levels.

Despite the elegant use of real data, the authors caution about limitations of their study, which include the fact that all subjects had type 2 diabetes and the overall degree of weight loss was rather modest. Thus, the model may well look different in subjects without diabetes or more extreme weight loss.
Nevertheless, as the authors discuss,
“…homeostatic feedback control of energy intake is likely a primary reason why it is so difficult to achieve large sustained weight losses in patients with obesity. Rather, weight regain is typical in the absence of heroic and vigilant efforts to maintain behavior changes in the face of an omnipresent obesogenic environment. Unfortunately, there is no evidence that the energy intake feedback control system resets or relaxes with prolonged maintenance of lost weight – an effect similar to the long-term persistent suppression of energy expenditure in weight-reduced humans. Therefore, the effort associated with a weight loss intervention persists until either body weight is fully regained or energy intake increases above baseline to match the homeostatic drive to eat.”
Thus, the key to finding long-term obesity treatments that work, will be to find means of permanently subverting or countering this feedback control system (which is exactly how medications or surgery theoretically work).
No wonder, that will power alone will rarely result in sustainable weight loss and will always require on-going (heroic?) effort in the cases where it does.
Edmonton, AB
*Papers published on bioRxiv are “preprints” before peer review, thus allowing other scientists to see, discuss, and comment on the findings immediately. Readers should therefore be aware that articles on bioRxiv have not been finalized by authors, might contain errors, and report information that has not yet been accepted or endorsed in any way by the scientific or medical community.



My Critical Review Of Critical Fat Studies: Obesity In Canada

obesity-in-canada-coverA few weeks ago, I was invited by the Editor of The Lancet Diabetes & Endocrinology to review Obesity in Canada, a collection of articles by Canadian and Australian authors, who identify themselves as “fat scholars” engaging in “critical fat studies”. (Edited by Jenny Ellison, Deborah McPhail, and Wendy Mitchinson).

Obviously, I have had multiple interactions with “fat scholars” over the years and have certainly always learnt a lot.

Indeed, I would be the first to admit that many of my own ideas about obesity, including the issue of whether or not obesity is a disease and, if so, how to define the clinical problem of obesity in a manner that does not automatically label a quarter of the population as “diseased”, has been shaped by this discourse.

Similarly, my own notions about obesity management, with a primary goal to improve health and well-being rather than simply moving numbers on the scale, are clearly influenced by ideas that first emerged from the “fat acceptance camp” (not exactly the same, but close enough).

Thus, there was certainly much in this compendium that I was already quite familiar with – which certainly made the reading of this 500 page volume most enjoyable.

Nevertheless, it is important to realise that “fat scholars” do not just see themselves as “scientists” – rather, they see the practice of “fat studies” as a political work, tightly (some might say dogmatically) bound to a frame of reference that is reminiscent of political “activism” rather than “science”.

Fat scholars (at least the ones represented in this volume) are not just critical of, but also appear most happy to discard the entire biomedical and population health discourse around obesity, as nothing more than (I paraphrase), “a thinly-veiled conspiracy by the biomedical establishment to create a moral panic that justifies the reassertion of normative identities pertaining to gender, race, class, and sexuality.

Accordingly, some fat scholars appear to be of the rather strong opinion that there is in fact no “global obesity epidemic” and even if there are perhaps a few more fat people around today than ever before, the health consequences of obesity are vastly overblown, and any recommendations or attempts to lose weight are not only ineffective but actually harmful.

Now, before you simply roll your eyes and decide to file away the whole exercise in the drawer that you reserve for global-warming deniers and anti-vaxxers, let me assure you that there is indeed a lot to be learnt from the discourse (at least I did).

For one, there are absolutely fascinating chapters on the history of fat activism in Canada (which apparently dates back to the early 70s), enlightening perspectives on Indigenous People’s encounters with obesity, the issue of “mother blaming”, and even a chapter on fat authenticity and the pursuit of hetero-romantic love in Vancouver.

There are stories about how kids and families experience childhood obesity intervention programs and how primary school teachers themselves struggle with being thrust into a role of being role models while struggling with their own personal response to the pervasive obesity messages.

Obviously, there are some ideas that may be harder to swallow than others.

Take for e.g, the notion that the “root cause” of fat phobia (at least according to fat scholars who rely on postmodern feminism, psychoanalysis, and queer theories), is simply a reflection of the femininity ascribed to body fat: because women need fat to menstruate, body fat can be seen as female reproductive material that, in patriarchy, must be contained, restrained, and ultimately eliminated.

Personally, I can no doubt think of a wide range of other “root causes” that would result in “fat phobia” and “weight stigma” without having to quite delve into feminism or queer theories – but that’s another story.

Or the notion that there is in fact no link between body fat and diabetes – something that is easily refuted by a host of experimental animal studies and clinical observations  (which, in the world of “fat scholars” do not appear to exist or are for some opaque reason deemed entirely irrelevant for the discourse).

Nevertheless, these “peculiarities” aside, I do admit that I found the book a very timely, relevant and enlightening read for anyone who is seriously interested in the issue of obesity and bold enough to step out beyond the typical biomedical discourse.

I would most certainly recommend this volume to people working in health policy and public health but also to clinicians, who seek to better understand some of the social aspects of the obesity discourse as it relates to their patients.

There is much in the volume that I perhaps disagree with or rather, see from a different perspective (I am after all a clinician) – however, openness to entertaining alternative views and ideas, and willingness to shift your own opinion and beliefs when new evidence emerges, is the defining characteristic of good scholarship – and I certainly remain a lifelong student.

Edmonton, AB

Disclaimer: I was given a complimentary copy of Obesity in Canada to review by the Lancet Diabetes & Endocrinology


Higher BMI In Identical Twins Increases Risk of Diabetes But Not Heart Attacks?

sharma-obesity-blood-sugar-testing1Increased BMI is often touted as a major risk factor for cardiovascular disease. However, this relationship is not as straightforward as most of us believe.

Now a study by Peter Nordström and colleagues, published in JAMA Internal Medicine, reports that a higher BMI in identical twins is associated with a greater risk for type 2 diabetes but not myocardial infarction or death.

The researchers looked at data from 4,046 monzygous twin pairs with discordant BMIs (difference >0.01 units) from the nationwide Swedish twin registry.

During a mean follow-up of 12 years, the rate of myocardial infarcts and deaths were similar in the twins with lower BMI compared to their higher BMI co-twin (5.0% vs. 5.2% and 13.6% vs. 15.6%, respectively).

This lack of difference remained true even when the researchers compared the extremes of BMI discordance and only considered twins with BMI greater than 30.

In contrast, both higher BMI and greater increase in BMI since 30 years before baseline was associated with greater risk of incident diabetes.

Given that diabetes is such a powerful risk factor for cardiovascular disease, one can only wonder why this did not translate into a higher cardiovascular risk in the higher weight twins.

One possible explanation, offered by the authors is that cardiovascular risk may have been well managed in these individuals thus minimizing any increased risk due to diabetes (or other BMI associated risk factors such as dyslipidemia or hypertension).

Indeed, it would probably have required a far larger group of twins (or much longer follow-up) to fully rule out higher cardiovascular risk in these twins.

Let us also not forget that BMI is a rather lousy measure of overall cardiovascular risk.

Thus, which the study is certainly compatible with the (genetics-independant?) role of higher BMI in the risk for diabetes, it certainly should not be interpreted as demonstrating that this increased risk in benign in terms of cardiovascular disease.

Edmonton, AB


Why I Am Luke Warm On World Obesity Day

world-obesity-day-2016Yesterday, was the 2016 World Obesity Day championed by the World Obesity Federation.

No doubt, obesity is a serious global issue, affecting millions of people worldwide.

However, the focus of World Obesity Day appeared to be almost entirely on childhood obesity – particularly on its prevention through policy measures.

While that is not an unreasonable goal (no doubt food advertising to kids needs to be reigned in and the global consumption of sugar needs to be reduced), the almost exclusive focus on childhood obesity in the announcement and materials released in support of obesity day, may deserve critical analysis.

Although increasing childhood obesity is no doubt an important issue, it cannot be seen in isolation from the far more prevalent adult obesity. Indeed, most of the current obesity epidemic is attributable to weight gain in adulthood – not to weight gain in kids.

Moreover, one could very well argue that much of childhood obesity is simply a direct consequence of adult obesity.

Thus, while the focus on childhood obesity may be strategically motivated (there is indeed very little public empathy for adults living with obesity), in my opinion, the almost exclusive focus on kids sends the wrong message.

For one, while I wholeheartedly support the public health policies to address obesity, I believe that adults with obesity are as deserving of our attention as are their kids.

By ignoring the adults living with obesity in their message, I fear the World Obesity Federation is sending (or rather reinforcing) the wrong message about adult obesity.

I cannot help but read between the lines, that while governments must urgently step in to eradicate childhood obesity, the millions of adults living with this chronic disease are perhaps less worthy of our attention.

Is this because we continue to feel that adults have done this to themselves? Is it because we believe that adults should be able to conquer obesity on their own? Or, Is this because we have essentially written them off as a lost cause?

I very much do believe that the millions of mothers, fathers, husbands, wives, friends, colleagues, and neighbours living with obesity, are as deserving of our compassion and our support as are their kids.

Rather than singling out kids as apparently the only (or even most deserving) group worthy of intervention, I would have liked to see the World Obesity Federation rally around the need for world-wide recognition of all of obesity as a chronic disease.

Indeed, I would have loved to see the World Obesity Federation declare discrimination of people living with obesity in health care, education, and other settings a human rights issue.

Most importantly, I would have hoped that the World Obesity Federation would have explicitly called for an end to the widespread practice of excluding obesity treatments from medical coverage in almost all health systems, and a rallying call for better education of all health professionals (and policy makers) in the basics of obesity medicine.

Like it or not, many of the kids and adolescents with obesity that the World Obesity Federation appears so concerned about will soon be young adults with obesity, with no access to obesity treatments, confronted by a generation of health professionals who still think obesity is a “lifestyle choice”.

While I do understand that initiatives like the World Obesity Day need to focus on an issue that is most likely to garner media interest and support, I also recognise that the focus on prevention of childhood obesity is merely going after the low-hanging fruit – the least controversial topic of all.

A bolder statement, one worthy of an organisation like the World Obesity Federation, would have addressed the main issue currently facing the millions of people living with obesity every day – the fact that their problem continues to be pooh-poohed publicly and institutionally as merely a “lifestyle” issue that they can easily solve by simply deciding to eat less and move more.

It is perhaps time that the World Obesity Federation takes all of obesity seriously – that would indeed be a message that I could rally behind.

Edmonton, AB


When The Risk of Treating Exceeds The Risk of Not Treating, Then Don’t

sharma-obesity-risk1To conclude my miniseries on the recent “Clinical Discussion” on obesity, published in the New England Journal of Medicine, I now turn to the final question – does this relatively healthy 29 year-old woman with a BMI of 32 warrant treatment?

And if yes, what treatment would you recommend.

This question cannot be answered without considering the following:

Often, we tend to focus on potential benefits of treatment, and so most of us would probably approach this question by comparing the potential benefits of treatment vs. the potential risks of not treating this patient – this is often referred to as the benefit-risk ratio.

When this ratio exceeds 1 (i.e. the potential benefits of treatment outweigh the potential risks of treatment), we would recommend treatment.

One could, however, also turn this into a risk-risk ratio.

Both, the decision to treat and the decision to not-treat bear risks.


Given that the woman in this case has Edmonton Obesity Stage 1 at best (borderline hypertension?), her mortality risk over 20 years is rather low.

For one, this means that treating her obesity would likely also have rather modest benefits (if any). In fact, there is currently no proven health benefit of even just modest weight loss in a patient like her.

Thus, we would certainly want to rule out treatments that carry any potential risk.

Clearly, obesity surgery,would not even remotely enter the picture.

Even the risk of medication, although much safer than anything we may have had before, is probably too high. Although the statistical risk for severe side effects (ranging from teratogenicity to pancreatitis – depending on the chosen medication) is rather low, it may still be substantially higher than doing nothing.

This leaves us with behavioural modifications, which would pose the lowest treatment risk (although it is important to remember that the risk of behavioural treatments is not zero: exercise can result in injury, a too restrictive diet could result in nutritional problems or, as some folks fear, trigger an eating disorder).

The most conservative approach would be to reassure her that her mortality risk is indeed rather low (certainly not warranting the risk of medication).

However, treatment decisions are not only guided by mortality risk – we also need to consider quality of life.

Despite being at low medical risk, it may well be that our patient is unhappy with her weight (although we have no information in this regard other than that she has made previous attempts at weight loss).

Exploring this further would certainly require a much deeper dive into how she feels about herself – her weight may not even be the real problem here.

Can she eat better and be more active? Sure, most of us can!

Would I want to see her again, perhaps in a year or so to see how she is doing – sure, even if just to confirm that she still has EOSS 1.

Beyond that, I would be guided by the principle of “first-do-no-harm” and probably leave it at that (at least for now).

Edmonton, AB


Obesity Is More Difficult To Diagnose Than You May Think

NN Benefits White Paper CoverContinuing in my miniseries on the recent “Clinical Discussion” on obesity, published in the New England Journal of Medicine, I now turn to the second question that we need to answer before jumping into giving our patient any advice about managing her weight.

The first question, as discussed in yesterday’s post, is to understand the possible “root-causes” of her weight gain, as these may not only have to be targeted during treatment but can also pose important barriers to management (e.g. emotional eating, depression, lack of time, stress, etc.).

Unfortunately, as I noted yesterday, the case presentation did not provide much in terms of helping us understand, why this patient has a BMI of 32 in the first place.

Not only did we not get any information regarding her weight trajectory, we were also only told that she eats out often and is largely sedentary – not really much to go on, given that the same could be said about the vast majority of people living in the US (or in Canada), irrespective of their size or weight.

As for the second question that we now need to answer, before giving any advice, is whether or not she even has a health issue that needs to be addressed.

Thus, while we may be led to believe that her BMI of 32 in itself justifies the diagnosis of “obesity”, we must remember that BMI is a essentially a measure of body size, in fact, not much better than a dress size.

Although statistical risk for certain health problems (e.g. diabetes, hypertension, joint problems, sleep apnea, etc.) may rise with increasing BMI, this relationship is far weaker than most people think.

Indeed, as we have previously noted, as many as 25-30% of individuals in the BMI 30-35 range may have no clinically significant health impairments whatsoever. This is particularly true for younger individuals and for women – out patient just happens to be a 29 year-old female.

Thus, it is in fact not all that surprising, that the case report goes on to note that Ms Chatham has neither a history of coronary artery disease nor diabetes (which would indeed be rather unusual if did), and, apart from a marginally elevated blood-pressure, her health status is largely “unremarkable”. Although not mentioned in the case vignette, we can perhaps also assume that all her lab values are normal.

Thus, even if we assume that the blood pressure reading is reliable, this information would at best put her at an Edmonton Obesity Stage 1, a stage where her long-term mortality risk would be almost indistinguishable from “normal”.

And, if we apply the actual WHO definition of obesity (the presence of excess or abnormal body fat that impairs health), we may in fact have to bend over backwards to diagnose this woman as having obesity at all.

So if there is no relevant health impairment from her BMI of 32, why is she even concerned about her weight?

Because, as we learn from the case study, she has been told indirectly, by her friends and family, that she is “overweight.”

Which brings me back to our question at hand: does this woman even have a health problem that needs to be addressed?

My answer would be a rather enthusiastic, “not really”.

We could of course leave it at that, and simply reassure her that she is pretty healthy (although she may perhaps want to have her blood pressure rechecked in the near future).

If however, she does persist in her intention to lose weight, and continues to insist that we advise her on what she can do to improve her health (which are really two very different questions), we may need to have a much longer discussion with her.

This is something we will look at tomorrow, when we address the third question:

What would be the best management plan for this patient?

Vancouver, BC


In Analyzing A Case We Should Worry More About The Why Than The What

cause-effectContinuing in this miniseries on the rather stereotypical case presented to us in the New England Journal of Medicine “Clinical Discussion”, I would like to approach it in the same manner that I approach any case.

The first question I ask in any encounter with a patient (once the problem has been stated, in this case a BMI of 32), is to try and figure out WHY the patient may have this problem.

Unfortunately, in this case we are only told WHAT the patient is doing but are given no indication as to WHY this may be the case.

Thus, we are told that she drinks alcohol, occasionally as many as 4 or 5 drinks in a week and enjoys eating out and orders take-out meals 8 to 12 times a week.

We are also told that she spends most of her day sitting in an office and tries to go to her fitness club about once a week.

Let us assume for a minute, that her current caloric intake does in fact exceed her caloric expenditure (which we don’t really know, as we are not told whether or not she is currently weight stable or continuing to gain weight – an important detail in any weight history – as we will see in a later post), and knowing that in most cases, weight gain tends to be a “calories-in” rather than a “calories-out” problem, let us for a minute focus on her diet.

Let us further assume that the main source of “excess” calories is indeed from the many meals that she eats out or orders in (the quality of which we know nothing about).

Then, the real question here is WHY she does not eat more home-cooked meals (which, we will simply assume would be a “healthier” choice).

We know she works all day, so is this simply a matter of convenience or lack of time?

Or does she lack basic cooking skills or even hates cooking?

Or does she just not want to eat alone (does she have a partner? kids? room mate?)?

We don’t know!

Nor do we know anything about the many possible underlying drivers of her (supposed) “overeating”.

Does she habitually skip meals and only eats when she is starving?

Is she an emotional eater, who overeats in response to stress or loneliness?

Does she even have stress?

Is she even lonely?

Or unhappy?

Or depressed?

Or anxious?

Or frustrated?

Or an impulsive eater?

Or hungry all the time?

Or never feels full after a meal?

Or craves sweets or chocolate?

Or is sleep deprived?

I would certainly be interested in all of this information to try and figure out WHY this patient is doing WHAT she is doing (assuming, that WHAT she is doing is even the real problem here).

I call this performing a “root-cause analysis” – and it is what I teach my students and residents to do – try to understand the WHY, not just he WHAT.

So, if you asked me, if based on the information presented in the case, I fully understand WHY this patient has a BMI of 32 – I can only honestly answer, that I have no idea.

I also know nothing about her family history (are her parents and siblings overweight? genetics? epigenetics?)

Nor do I know anything about her weight trajectory (was she overweight as a child? gain excess weight during puberty? as an adult? aas there an adverse life-event that prompted the weight gain? does the problem still exist?)

Really, all we can do based on the information presented in this case, is to focus on the presumptive WHAT (eating out and not exercising), which is perhaps fine, if my generic approach to helping this patient is simply going to consist of advising her to, “eat at home and go to the gym”.

Sadly, that approach will prove to be about as effective as telling someone with depression to cheer up or telling someone with anxiety disorder to stop worrying and be happy.

Tomorrow, I will turn to the second question that I always ask myself, namely, does this patient even have a health problem that needs to be addressed?

Edmonton, AB