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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.



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


Stereotypical Stigmatizing Case Histories Are Not Useful For Teaching Doctors About Obesity

living-in-usa-spiral400bYesterday, I posted about the “Clinical Discussion” of obesity management, presented to us by the venerable New England Journal of Medicine.

I wrote about how the ignorant and moralizing “opinion” of one of the discussants, devoid of even the smallest insight in to the complex sociopsychobiology of this chronic disease, is exactly the kind of “thinking” that is holding back the field (and has been for decades).

But these are not the only problems with the “Clinical Discussion”.

Rather, the problems start with the very choice and description of the “case”.

Indeed, the case warrants a careful line-by-line analysis, to reveal just how the use of the “stereotypical” depiction paints a picture of what (as we will see in a later post), could well turn out to be a much more complicated case than either of the discussants acknowledge.

As we are told,

Ms. Chatham is a 29-year-old woman who recently joined your practice; this is her second visit to your clinic.

In other words, this is a young woman, whose life you know virtually nothing about, not that this should ever stop you from stating your sound medical opinion.

She made today’s appointment to discuss how she can lose weight and whether there are medications that she can take to aid in weight loss.

In other words, a typical “fat” patient looking for a “quick fix” via “diet pills”?

She is relatively healthy, except for a history of childhood asthma.

Did the asthma play any role in her weight gain? Did it limit her physical activity as a kid? Was she on anti-allergic drugs or even systemic steroids that may have led to weight gain? Your guess is as good as mine.

She says that she has been told indirectly, by her friends and family, that she is “overweight.”

Because, obviously, she does not own a mirror, never shops for clothes, and has probably never given her shape or size a second thought, and therefore, needs to be “told” by the good people around her (and perhaps on occasion by perfect strangers she may just happen to meet on the street), that she has a serious health problem and needs to urgently see a doctor.

She has tried several popular diets without success; each time, she has lost 4.5 to 6.8 kg (10 to 15 lb) but has been unable to maintain the weight loss for more than a few months.

Which, I’m guessing, simply goes to prove her lack of motivation and effort. Obviously, like most “fat” people, she is just too weak-willed to maintain weight loss and apparently always gives up far too soon. Never mind, that this is exactly what happens to 95% of people (skinny or fat) who lose weight and never mind, that (as some of us now realise) there is in fact a complex neurohormonal physiology, which tightly regulates body weight and is there solely for the purpose of effectively “defending” against weight loss.

She does not have a history of coronary artery disease or diabetes.

Which would in fact be surprising, given that she is a 29 year-old woman!

She has a regular menstrual cycle.

Which means what exactly? Are we supposed to rule out PCOS or fertility issues based on this clinical “pearl”?

She does not take any medications or nonprescription supplements.

So at least we know that she cannot simply blame her weight gain on any current medications.

She does not smoke but does drink alcohol, occasionally as many as 4 or 5 drinks in a week, when she is out with friends.

Which you could also say about millions of other people (including myself), irrespective of their BMI or health status – it’s what people do!

She tells you that she “watches what she puts in her mouth”…

Which, of course we should have a hard time believing, because as we all know, “fat” people are habitual liars when it comes to what they “tell” us about their diets.

…and reads the nutritional labels on food packaging.

or, at least that’s what she “tells” us – you’re welcome to believe her or not.

However, she enjoys eating out and orders take-out meals 8 to 12 times a week.

Wow! Here we have a “fat” person who actually “enjoys” eating out – as many times as (hold your breath) once or twice a day – and that, despite claiming to read food labels! Never mind that this is exactly how 99.9% of the US population happens to eat (no matter what their size or health status) – clearly, this irresponsible behaviour must change if there is to be any hope for her!

She works as a computer programmer and spends most of her day sitting in an office.

There we have it – typical “sedentariness” a well-known “cause” of obesity (or so we are told), because (as should be obvious to anyone who understands the complexity of energy homeostasis), all people who sit in offices (not to mention the now immortalised 400 lb “hacker”), struggle with their weight.

She belongs to a fitness club and tries to go there about once a week but notes that her attendance is inconsistent.

Because, of course, it’s typically the fat people with gym memberships, who never show up for training. Also relevant, because most of us continue to believe that exercise is the best way to lose weight.

On physical examination, her vital signs are unremarkable except for a blood-pressure measurement of 144/81 mm Hg.

Which we must obviously assume to be reliable, as the docs have certainly ruled out the presence of “White-Coat” hypertension and bothered to ensure that they are indeed using an appropriate cuff size.

She is 1.7 m (5 ft 7 in.) tall and weighs 92 kg (203 lb), and her body-mass index (BMI; the weight in kilograms divided by the square of the height in meters) is 32.

Which contains about as much clinically valuable information as telling us that she is a size 16.

Her waist circumference is 94 cm (37 in.).

Another piece of useless information, especially in an otherwise healthy woman.

There is no peripheral edema.

Which, I guess, clearly tells us that she can forget about using “fluid retention” as an “excuse” for her weight.

The rest of the examination is unremarkable.

There you have it – with this information in hand, we are now clearly poised to give her meaningful clinical advice to help her better manage her weight.

What surprises me about this (apparently “typical”) case history, is that the editors of the New England Journal of Medicine, otherwise so concerned with brevity, did not simply decide to shorten the “case” to the following:

“Ms. Chatham is a pretty healthy 29-year-old working woman, who happens to live in the USA.”

That one line would in fact contain about all of the information we now have about Ms. Chatham, the difference being, that this statement is actually better, in that it is elegantly crafted to avoid the use of “stereotypical” fat-shaming language and imagery.

Furthermore, this sentence, quite like the “case”, is also void of any indication of the actual complexity that even “simple obesity” can present in clinical practice (which, I perhaps mistakenly, assumed would have been the whole point of the Clinical Discussion in the first place).

Is anyone curious as to the information that I would really liked to have about Ms. Chatham to come up with advice that would actual help her?

Then, please stay tuned for tomorrow’s post.

Edmonton, AB


Total Ignorance About Obesity Does Not Stop Doctors From Preaching About It

out_to_lunchIf anyone thought that the medical establishment is slowly but surely embracing the notion that obesity (not unlike hypertension or type two diabetes), is a complex chronic disease that requires proper medical management,  a recent Clinical Discussion published in the New England Journal of Medicine should be a clear sign that we are still a long way from home.

The presented case, is that of a 29-year-old woman with a BMI of 32, who has a history of past weight loss attempts, but otherwise appears in fairly good health. She does not smoke but does drink alcohol on occasion. She says that she “watches what she puts in her mouth” and reads the nutritional labels on food packaging. She eat out and orders take-out meals 8 to 12 times a week. She has a sedentary job but belongs to a fitness club which she attends irregularly. On physical examination, her blood-pressure is mildly elevated (144/81 mm Hg). The rest of the examination is unremarkable.

The two discussants are: Dr. Kushner, a past-president of The Obesity Society and one of the world leading medical authorities on obesity management from Northwestern University, Chicago and a certain Dr. Gordon Schiff, from Harvard Medical School, who, as far as I can tell from his short bio, has no apparent credentials in obesity management whatsoever.

Dr Kushner, takes a rather sensible and otherwise rational approach to this patient including counselling her on the core principles of weight management, such as goal setting, building a plan for reduced caloric intake, increasing physical activity, reducing sedentary activity, and using self-monitoring strategies, and goes on to broach the topic of weight-loss medication, which may provide additional benefits.

In rather sharp contrast, Dr. Schiff launches straight into nothing short of a moralistic tirade on the evils of promoting or prescribing drugs to treat obesity, mainly for the reason that doing so,

does a disservice to our patients, society, and ourselves


violates nearly every principle of careful, conservative prescribing, and they may well put patients at risk.

His main argument regarding risk, is the rather appalling history of weight-loss drugs – essentially the story line is that, because weight-loss drugs in the past have raised safety concerns, current or even future drugs for obesity must in fact all be harmful. 

I find this line of argumentation about as coherent as stating that, just because of the harmful history of mercurial diuretics or arsenic anti-syphillic agents, we should be vary of any drugs that could potentially help patients fight fluid retention or venereal disease.

No matter that we are now talking about a completely different and unrelated classes of diuretics or antibiotics – history should have taught us that trying to fight fluid retention or venereal disease with medications will only put patients at harm.

Indeed, to follow Dr. Schiffs deeply insightful line of reasoning, we have just to look at the safety concerns with diuretics (potentially life-threatening hypokalemia, hyponatremia, and dehydration – not to mention gout or impotence) or antibiotics (lethal anaphylaxis, seizures, diarrhea, fungal infections) to clearly understand that even the though of using medications to treat fluid retention (irrespective of the cause) or venereal infections (irrespective of the etiology) must indeed “violate nearly every principle of careful, conservative prescribing, and may well put patients at risk.”

So how does Dr. Schiff propose to help this patient?

By recommending a

realistic, supervised, intensive, supportive plan to moderate caloric intake and exercise regularly, which often works as well as drugs without the negative effects and offers additional, proven positive health benefits.”

(Or, in other words – “eat less – move more”).

I have no doubt that in his, probably very busy clinical practice, Dr. Schiff routinely recommends that his patients with edema strictly monitor their fluid intake, while his STD patients are surely benefiting from his recommendation to faithfully abstain from any form of sexual intercourse.

After all, as Dr. Schiff argues, we should not even remotely consider medically treating conditions that affect millions of people just because they affect millions of people. Doing so would clearly be doing a “disservice to our patients, society, and ourselves”.

I am sure people living with obesity worldwide will be eternally grateful to Dr. Schiff for his forward thinking and evidence-based insights into the well-documented spectacular effectiveness (and I don’t mean efficacy) of “eating less and moving more” as the lasting “cure” for excess weight.

We must indeed all be deeply thankful to the esteemed New England Journal of Medicine for bringing us this timely ounce of wisdom, that is already having me rethinking my own practice.

Edmonton, AB