Monday, March 10, 2014

Will Replacing Vending Machines With Slot Machines Reduce Childhood Obesity?

slot machineIn Western countries, both childhood and adult obesity have long been linked to socioeconomic status – in short – not having enough money (and/or education) can make you fat.

This may be the most obvious explanation for an intriguing finding by Jessica Jones-Smith and colleagues published in JAMA, showing that opening or expansion of American Indian-owned casinos were associated with a significantly decreased risk of childhood obesity in those communities.

The basis for this hypothesis was the simple fact that for some American Indian tribes in the US, casinos provide a significant source of income for the people living in those communities.

The researchers looked at repeated cross-sectional anthropometric measurements from fitness testing of American Indian children (aged 7-18 years) from 117 school districts that encompassed tribal lands in California between 2001 and 2012, of which 57 gained or expanded a casino, 24 had a preexisting casino but did not expand, and 36 never had a casino.

Using changes in the number of slot machines per capita as a measure of economic expansion (each slot machine was associated with an increase of around $550 in per capita annual income), the researchers found that every additional slot machine per capita reduced the probability of childhood overweight and obesity by about 0.2 percentage points.

Given that on average the opening or expansion of a casino resulted in about 13 additional slot machines per capita – the average reduction in obesity probability would be about 2.6% points.

Obviously, as the authors acknowledge, factors other than simple economics may have played a role in this relationship.

Thus, as always with these type of studies,  assuming a direct causal relationship between adding slot machines and reducing childhood obesity obesity may be too simplistic.

Less critical observers may nevertheless jump to the conclusion that battling childhood obesity in tribal communities may be as easy as replacing vending machines with slot machines.

@DrSharma
Copenhagen, DK

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Wednesday, March 5, 2014

Why The 500% Increase in Severe Obesity Should Concern Us All

sharma-obesity-waiting-timeAs someone working in a tertiary care bariatric clinic, I have often been accused of just seeing the tip of the iceberg.

Unfortunately, it is this “tip” that is growing the fastest, when it comes to the increase in obesity rates across Canada.

Thus, a paper by Laurie Twells and colleagues from Memorial University, St John’s, Newfoundland, published in CMAJ Open, not only predicts that overall obesity rates in Canada will continue to grow well into 2019, but also shows that between 1985 and 2011, the rates of Canadian adults with a BMI greater than 40 have increased from 0.3 to 1.6%.

Over the same time period, rates of Canadians with Class I and  Class II obesity have increased from from 5.1% to 13.1%, from 0.8% to 3.6%.

So, while the efforts in obesity prevention may or may not eventually lead to fewer people getting obese in the first place, our strategies are miserably failing those, who already have the problem.

This should come as no surprise, as Canada has yet to come up with a coherent strategy to address adult obesity.

As the authors note, there is indeed a wide variability between provinces when it comes to access to obesity treatments, irrespective of whether this is bariatric surgery or behavioural programs in primary care.

There also continues to be a significant deficit in training and education of health professionals in best-practices in the prevention of weight gain and obesity treatments.

Unfortunately, the impact of this lack of access and resources affects those the most, who already have the problem. They neither have the time to wait for prevention measures to kick-in nor do I expect measures aimed at prevention to lessen their health burden – they need treatments.

It would of course help if we actually had better treatments. Given a 95% failure rate of “Eat-Less-Move-More” approaches to obesity management, there is no doubt that the sooner we find more effective treatments, even if they only help prevent progression in those who already have the problem, the better for everyone.

After all we are talking about our families, friends, colleagues, neighbours – people, whose struggles with this condition should concern us all.

@DrSharma
Edmonton, AB

Please help this penguin grow wings and fly

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Wednesday, February 26, 2014

Why The Energy Balance Equation Results In Flawed Approaches To Obesity Prevention And Management

1st law of thermodynamics obesityAllow me to start not with the first law of thermodynamics (energy cannot be created or destroyed) but rather, the second law of thermodynamics, according to which entropy (best thought off as a measure of disorder), in any closed system, increases till it ultimately reaches thermodynamic equilibrium (or a state of complete disorder).

As some of us may recall from basic biology, the very definition of “life”, which tends to move from a state of lesser organisation to a state of higher organisation, is that it appears to defy the second law of thermodynamics (this is often referred to as “Schroedinger’s Paradox”).

In actual fact, we can easily argue that the second law does not apply to living organisms at all because living organisms are not closed systems and life’s complex processes continuously feed on its interactions with the environment.

Yet, when we consider the first law of thermodynamics and how it applies to obesity, we seem to forget the fact that we are again dealing with a complex living organism.

Thus, in what has been referred to as the “Folk Theory of Obesity”, we simply consider weight to be a variable that is entirely dependent on the difference between energy input and energy output (or “calories in” and “calories out”). And in our arithmetical thinking, we consider “energy in” and “energy out” as simple “modifiable” or “independent” variables, which if we can change, will result in any desired body weight.

In fact, our entire “eat-less-move-more” approach to obesity is based on this concept – the central idea being, that if I can effectively move “energy in” and “energy out” in the desired directions, I can achieve whatever weight I want.

This notion is fundamentally flawed, for one simple reason: it assumes that weight is the “dependent” variable in this equation.

However, as pointed out in a delightful essay by Shamil Chandaria in my new book “Controversies in Obesity“, there is absolutely no reason to assume that weight is indeed the “dependent” or “passive” player in this equation.

Indeed, everything we know about human physiology points to the fact that it is as much (if not more) body weight itself that determines energy intake and output as vice versa.

Generally speaking, heavier people tend to eat more because they have a stronger drive to eat and/or need more calories to function – in other words, body weight itself may very much determine energy intake and output (and not just the other way around).

Similarly, losing weight tends to increase hunger and reduce energy expenditure – or in other words, changes in body weight can very much determine changes in energy intake and expenditure (and not just the other way around).

Thus, the idea that we can control our body weight by simply controlling our energy intake and output, flies in the face of the ample evidence that it is ultimately our physiology (in turn largely dependent on our body weight) that controls our energy intake and output.

Thus, to paraphrase Chandaria’s key argument, it is not so much about what “energy in” and “energy out” does to our body weight – it is more about what our body weight does to “energy in” and “energy out”.

Once we at least accept that this equation is a two-way street, rather strongly biased towards body weight (or rather “preservation of body weight”) as the key determinant of “energy in” and “energy out”, we need to ask a whole different set of questions to find solutions to the problem.

No longer do we restrict our focus to the exogenous factors that determine “calories in” or “calories out” (e.g. our food or build environments) or see these as the primary targets for decreasing caloric intake or increasing caloric output.

Rather we shift our focus to the physiological (and psychological) factors (often dependent on our body weights) that ultimately dictate how much we “choose” to eat or expend in physical activity.

Chandaria’s essay goes on to discuss the many “derangements” of physiology that we know exist in obese individuals (and probably already exist in those at risk for obesity), including leptin resistance, impaired secretion of incretins like GLP-1, insulin resistance, alterations in the hypothalamic-pituitary-adrenal (HPA axis), and sympathetic activity. (Any keen student of human physiology or psychology should have no problem further extending this list.)

In Chandaria’s view, it is these physiological (and psychological) processes that ultimately determine whether or not someone is prone to weight gain or ultimately gains weight.

In fact, the only factor that determines why two individuals living in the same (obesogenic) environment will differ in body weights (even when every known social determinant of health is exactly equal), is because of their individual physiologies (and psychologies) which ultimately determine their very own individual levels of “energy in” and “energy out” (and how their bodies respond to it).

Readers may be well aware that in tightly controlled feeding studies, the same absolute amount of extra calories can result in very different amounts of weight gain.

Similarly, the exact same amount of caloric deficit will result in widely different amounts of weight loss.

Ignoring this basic fact of human nature distracts or, at the very least, severely limits us from finding effective solutions to the problem.

This “physiological” view of the first law of thermodynamics should lead us away from simply focussing on the supposedly “exogenous” variables (“energy-in” and “energy-out”) but rather draw our attention to better understanding and addressing the biological (and psychological) factors that promote weight gain.

This would substantially change the aims and goals of our recommendations.

Thus, for e.g., rather than aiming exercise recommendations primarily at burning more calories, these should perhaps be better aimed at improving insulin sensitivity and combating stress. Thus, rather than counting how many calories were burnt on the treadmill, the focus should be on what that dose of exercise actually did to lower my insulin or stress levels.

Indeed, we may discover that there is a rather poor relationship between the amount of calories burnt with exercise and the physiological or psychological goal we are trying to achieve. While more exercise may well help burn more calories (which I can eat back in a bite or two), it may do little to further improve insulin resistance or combat stress thus leaving my weight exactly where it is.

Similarly, rather than trying to restrict caloric intake, dietary recommendations would be based on how they affect human physiology (e.g. gut hormones, reward circuitry or even gut bugs) or mood (e.g. dopamine or serotonin levels).

In other words, fix the physiology (or psychology) and “calories in” and “calories out” will hopefully fix themselves.

Given that our past efforts primarily focussing on the “energy in” and “energy out” part of the equation have led nowhere, it is perhaps time to focus our attention and efforts elsewhere.

Or, as I often say in my talks, “We’re not talking physics here – we”re talking physiology – that’s biology messing with physics”.

We cannot mess with the physics but we sure can mess with the biology.

@DrSharma
Edmonton, AB

Shamil A. Chandaria: The Emerging Paradigm Shift in Understanding the Causes of Obesity. In Controversies in Obesity. Eds: Haslam DW, Sharma AM, Le Roux CW. Springer 2014

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Monday, February 24, 2014

Why The Energy Balance Equation Is a Dangerous Lie, an Embarrassment to Health Professionals, and an Insult To Our Patients

Controversies in ObesityThe title of today’s post paraphrases the title of a chapter by Damian Edwards, in our new book “Controversies in Obesity” (published by Springer), which I co-edited with my friends and colleagues David Haslam and Carel le Roux.

This chapter by Damian Edwards, Board Member of the National Obesity Forum (UK) and Professional Member of the NICE Public Health Programme Development Group, stands for the type of thought-provoking essays that readers can expect to find in this book.

Recognizing that our present strategies to prevent and clinically manage obesity are nothing short of a miserable failure on all fronts (anecdotal “success” stories apart), we challenged some of the most-prominent present-day thought-leaders in obesity to come up with their most provocative (and perhaps outrageous) ideas about what is really causing the obesity epidemic and how we may have to fundamentally rethink our approaches to preventing and managing it.

To those working in the field, names like Boyd Swinburn, J-P Despres, Richard Atkinson, Michael Lean, Susan Jebb, John Dixon, Henry Purcell, Stephen Rossner, Kirsi Pietilainen, Nikhil Dhurandhar, or the many other authors of this book need no introduction.

These authors are not quacks or self-appointed experts peddling the next fad diet or demonizing [enter your favourite nutrient here]. They are all widely recognized and respected thought-leaders with the highest academic credentials, bold enough to openly challenge conventional wisdom and “folksy” theories about obesity based on their interpretation of the latest scientific insights into this complex chronic disease.

I am happy to say that this short volume, although primarily written for a technical audience (which explains the relatively high price), may also be of interest to educated lay readers – especially those, willing to open their minds to scientific ideas and theories that go against mainstream thinking (including the simplistic and paternalistic “Eat-Less-Move-More” nonsense widely propagated by public health and clinical professionals alike).

Obviously, controversies would not be controversies if everyone agreed. Indeed, even I don’t fully agree with all of the theses and arguments presented in these essays. But this only makes for an even more stimulating and provocative read.

Look for more on Edwards’ arguments (and the explanation to the title of today’s post) in coming posts.

@DrSharma
Edmonton, AB

To order Controversies in Obesity directly from the publisher – click here (half-price promotion runs till March 10, 2014)

To order Controversies in Obesity through Amazon – click here

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Wednesday, February 5, 2014

Obese Kids Drink As Much Pop As Skinny Kids?

sharma-obesity-beveragesAmong all of the popular targets for population-based solutions to the obesity dilemma, sugar-sweetened beverages (SSB) probably head the list.

There is indeed no arguing with the fact that the sugar in these beverages adds a substantial amount of calories to the average Canadian’s diet – calories, with little (if any) nutritional value. Thus, in any simplistic equation of  ”calories in and calories out”, SSBs would certainly stand out as a prime candidate for driving obesity.

Unfortunately, this notion (at least the simplistic variants of this notion) are not as unequivocally supported by the actual research on this issue, as some would have us believe.

Case in point is the latest study on this issue by Lana Vanderlee and colleagues from the University of Waterloo School of Public Health (host of the upcoming 4th National Obesity Student Meeting, June 18-21, 2014), published in the Journal of School Health.

The study looks at data from 10,188 youth (ages 13-18) from Hamilton and Thunder Bay, Ontario, and Prince Edward Island (PEI) in 2009 to 2010, who answered 12 questions regarding beverage consumption during the previous day, along with self-reported height, weight, physical activity levels, and demographic information.

While four out of five youth reported to have consumed at least one SBB on the previous day, almost one in two reported consuming three or more!

Although there were interesting geographic differences in SSB consumption, the researchers found virtually no relationship between BMI and SSB consumption, no matter how they analyzed the data.

Funnily enough, PEI, where kids reported the lowest SSB consumption, turned out to have the highest number of overweight kids.

Despite all the usual caveats with studies based on self-reported rather than objectively measured data, one thing is clear: if SSBs are indeed a relevant driver of the obesity epidemic, the data certainly don’t shout it out.

Obviously, one explanation could well be that the methodology of the study was not robust enough to identify this relationship (although I am certain that had a positive relationship been found, this study would  have been widely paraded as conclusive evidence to support the immediate ban of SSBs).

On the other hand, a rather simple explanation for this finding may be that no such relationship exists. Indeed, it is scientifically not at all unreasonable, when your data fail to support your hypothesis, to question the hypothesis.

This is not to say that copious consumption of SSBs may not be detrimental to health – that may well be the case.

But it does seem that the popular story line suggesting that SSBs are anywhere as important a “cause” of the obesity epidemic as proponents of this hypothesis make them out to be, certainly needs to be taken with a grain of salt.

This issue becomes even more important, if such efforts distract us from identifying and addressing the “real” causes of the problem (which I am willing to wager, in the end, may well have surprisingly less to do with either diet or physical activity than we think).

@DrSharma
Edmonton, AB

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In The News

Diabetics in most need of bariatric surgery, university study finds

Oct. 18, 2013 – Ottawa Citizen: "Encouraging more men to consider bariatric surgery is also important, since it's the best treatment and can stop diabetic patients from needing insulin, said Dr. Arya Sharma, chair in obesity research and management at the University of Alberta." Read article

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