Friday, March 7, 2014

Leipzig Forging Its Way As Leaders in Obesity Research

Seal Faculty of Medicine, University of Leipzig, GermanyThis week, for the 5th consecutive year, I have had the privilege of participating in an extensive review of the obesity research program at the University of Leipzig.

I believe that it is fair to say, that starting from scratch, this centre has certainly shown a most remarkable growth and advancement in both fundamental and clinical aspects of obesity research.

It is indeed an honour to have had the opportunity to help evaluate and guide this world-class research program over the past five years.

It is particularly heartwarming to see how much emphasis this program has placed on supporting the career development of the next generation of obesity researchers in Germany.

As the program goes into the renewal phase for hopefully acquiring funding for the next five years, here is a link to past posts on their achievements.

@DrSharma
Leipzig, Germany

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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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Friday, February 28, 2014

What Stops Young Immigrants From Being Physically Active?

sharma-obesity-varsity-sportsAs a “not-so-young” immigrant myself, this is a topic that certainly caught my intention.

I can think of a lot of reasons why someone moving to a place like Canada (especially if you moved from somewhere warmer) would be less active but is this really true?

Sadly, it is, as nicely demonstrated in a paper by CON Bootcamper Atif Kukaswadia and colleagues from Queen’s University, Kingston, Ontario, just published in PLOS one.

The researchers looked at Cycle 6 (2009–2010) of the Canadian Health Behaviour in School-Aged Children Study and the 2006 Canada Census of Population, which included over 23,000 kids from grades 6–10 in over 400 schools.

It turns out that kids born outside of Canada were about 25% less likely to be active than peers born in Canada.

On a more positive note, however, physical activity levels did tend to increase the longer the kids reported living in Canada.

Nonetheless, South and East Asian youth were significantly less active, regardless of time since immigration.

Although Kukaswadia and colleagues, in time honoured researcher mode, conclude by noting that “more research is needed” to determine the mechanisms by which these differences occur and to identify barriers to physical activity participation among immigrant youth, they do offer a few speculations:

1) being involved in different forms of physical activity.
2) cultural differences in what constitutes physical activity.
3) ethnic differences in extracurricular activity involvement.

I would certainly add that one of the key cultural determinants may well be the stronger emphasis that East and South Asian parents generally place on academic versus athletic performance – the latter being often looked at as a hobby or past-time rather than an essential part of growing up.

I am sure my readers may have other ideas as to the reasons for this observation.

@DrSharma
Edmonton, AB

Kukaswadia A, Pickett W, Janssen I (2014) Time Since Immigration and Ethnicity as Predictors of Physical Activity among Canadian Youth: A Cross-Sectional Study. PLoS ONE 9(2): e89509. doi:10.1371/journal.pone.0089509

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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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Tuesday, February 25, 2014

Can Portion Sizes Really Drive Weight Gain?

out_to_lunchEven a casual visitor to North America will unlikely have missed the humongous portion sizes (enough to feed a small family) routinely served up at chain restaurants (and most other places).

Indeed, in any “folksy” discussion of what drives obesity, portion sizes are sure to be on the plate.

In addition, cutting portion sizes is one of the most common pieces of advise given to anyone trying to lose weight.

But how important are portion sizes in promoting weight gain?

This is where a new randomized controlled trial designed to test this hypothesis in free living individuals may provide some answers.

In this study, just published in OBESITY, Simone French and colleagues from the US and UK randomly assigned 233 volunteers (mean BMI ~30) to one of three lunch size groups (400 kcal, 800 kcal, and 1,600 kcal) or to a no-free lunch control group for 6 months.

The study was “disguised” as an intervention to test the “feasibility of providing box lunches to employees at a large metropolitan medical complex.

The free box-lunches were provided Monday to Friday. Fifteen different box lunch menus were created and menus were implemented on a 3-week repeating cycle. However, the conditions were on different cycles, so that participants assigned to different conditions could not directly compare their lunch box items on any given day. The same size box was used in all three conditions. Only water was served as a beverage.

As one may expect, people with the 800 and 1600 kcal lunches ate more that those with the 400 kcal lunches both at lunch and as total daily energy.

Interestingly however, while those on the 1600 kcal managed to gain about 2 pounds over the 6 months, there was no weight change in those eating fewer calories.

Incidentally, the individuals in the control group also gained about 2 pounds suggesting that the 1600 kcal was closer to what these folks were generally served as their “usual” meals.

Thus the authors rightly conclude that weekday exposure for 6 months to a 1,600 kcal lunch can cause significant increases in total energy intake and a weight gain.

On the other hand, the study also shows that simply limiting the size of lunch may not result in the significant weight loss that people may hope for.

I would interpret the overall findings as supporting the notion that our body’s homeostatic systems are much better in preventing weight loss than in defending against weight gain. Thus, while it takes a hefty 1600 kcal free lunch to drive weight gain, our bodies appear quite competent in regulating our body weights when served free lunches in the 400-800 kcal range.

On a side note, all box-lunch recipients increased their intake of fruits and vegetables compared to the control group – clearly showing (as noted in a recent previous post) that simply eating more fruits and veggies alone is not a viable recipe for weight loss (or even preventing weight gain).

So will efforts to reduce portion sizes (of weekday lunches) pay off in terms of preventing weight gain? Probably.

Will efforts to reduce portion sizes (of weekday lunches) help reduce obesity? Probably not.

@DrSharma
Edmonton, AB

ResearchBlogging.orgFrench SA, Mitchell NR, Wolfson J, Harnack LJ, Jeffery RW, Gerlach AF, Blundell JE, & Pentel PR (2014). Portion size effects on weight gain in a free living setting. Obesity (Silver Spring, Md.) PMID: 24510841

 

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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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