Friday, March 28, 2014

Why Watching Your Kid’s Media Use May Affect Their Weight

sharma-obesity-family-watching-tvElectronic media consumption has been linked to childhood obesity – but does monitoring your kid’s media use affect their body weight?

This question was now addressed by Tiberio and colleagues in a paper published in JAMA Pediatrics.

The researchers examined longitudinal data from a community sample in the US Pacific Northwest that indluced 112 mothers, 103 fathers and their 213 kids aged five to nine years old.

The data included what parents reported on their general monitoring of their children (whereabouts and activities), specific monitoring of child media exposure, children’s participation in sports and recreational activities, children’s media time (hours per week), household annual income, and educational level as well as parental BMI was recorded.

It turns out that maternal (but not paternal) reports of monitoring their kid’s media exposure was associated with lower BMI z scores at age seven as well as less weight gain between five and seven years of age.

These findings remained significant even after adjustment for several other variables including total media time as well as sports and recreational activities.

From these findings, the authors conclude that,

Parental behaviors related to children’s media consumption may have long-term effects on children’s BMI in middle childhood.

And that these finding,

“…underscore the importance of targeting parental media monitoring in efforts to prevent childhood obesity.”

I would not go quite that far for several reasons.

Firstly, associations do not prove causation. In addition, we don’t know much about other aspects of parenting style from this study that may well also have impacted body weight.

Thus, we could well speculate that moms who monitor their kid’s media consumption may also be more adamant about bed times, healthy eating, or even just spending more time talking to or listening to their kids – all of which may well have positive effects on their kid’s weight.

This is why simply getting parents to be stricter about monitoring their kid’s media consumption may not result in better weights at all.

As always, I  find it disconcerting when epidemiological data is used to predict what may or may not happen when interventions target a proposed “cause”.

Nevertheless, for anyone interested in this topic, the following event may be of interest:

Details:

On May 1, 2014 the Alberta Teachers’ Association, in partnership with the Alberta Centre for Child, Family and Community Research, is pleased to invite Dr. Michael Rich and Dr. Valerie Steeves to Edmonton for a discussion on how technology is impacting children, youth and society. This is a continuation of our series of evening public lectures with world renowned and distinguished speakers that has included Sir Ken Robinson, Sherry Turkle, Yong Zhao, Jean Twenge, and Carl Honore.

Dr. Valerie Steeves, Associate Professor, University of Ottawa, and principal investigator of the largest Canadian research study on children & teens’ online habits.

Young Canadians in a Wired World (2013) – Explore the highlights of Dr. Steeves’ pioneering Canadian research on children & teens’ online habits.

Ø  Cyberbullying: Dealing with Online Meanness, Cruelty and Threats

Ø  Online Privacy, Online Publicity 

Ø  Life Online

Dr. Michael Rich, Associate Professor of Pediatrics at Harvard Medical School and Associate Professor of Society, Human Development, and Health at Harvard School of Public Health, Boston, United States.

Ø Centre on Media and Child Health – Explore Dr. Rich’s extensive work on behalf of Children’s Hospital Boston, Harvard Medical School and the Harvard School of Public Health:

Ø CBC national panel discussion on Youth and Technology (February 2014):

Ø Ask the “Mediatrician” a question

There will also be a public lecture on Thursday evening May 1, 2014 entitled “Connected or Disconnected? Technology and Canadian Youth”.

Who: Dr. Michael Rich (Harvard University) and Dr. Valerie Steeves (University of Ottawa)

When: Thursday Evening, May 1, 2014

Where: Barnett House, Alberta Teachers’ Association, 11010 – 142 street NW Edmonton, Alberta

•6:00 pm Registration and reception (hors d’oeuvre and no host bar)

•7:00 pm to 9:30 pm Public lectures and discussions

Order Tickets ($10) Online at http://www.event-wizard.com/promiseperil2014/0/register/

For further information or any questions about this event please email karin.champion@ata.ab.ca or call 1-800-232-7208.

@DrSharma
Edmonton, AB

ResearchBlogging.orgTiberio SS, Kerr DC, Capaldi DM, Pears KC, Kim HK, & Nowicka P (2014). Parental Monitoring of Children’s Media Consumption: The Long-term Influences on Body Mass Index in Children. JAMA pediatrics PMID: 24638968

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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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Tuesday, March 4, 2014

Can Eating More Fat Make You Leaner?

sharma-obesity-visceral-fat-mriYes, if the excess fat is poly-unsaturated – no, if it is saturated.

At least this was the finding in an overfeeding study conducted by Fredrik Rosqvist and colleagues from the Uppsala University, Sweden, published in DIABETES.

The study with the memorable acronym LIPOGAIN, was a double-blind, parallel-group, randomized trial involving 39 young normal-weight individuals who were overfed muffins either high in saturated fats (palm oil) or in n-6 poly-unsaturated fats (sunflower oil) for seven weeks.

The number of muffins that each subject had to consume were individually adjusted to ensure that each subject increased their body weight by about 1.5 Kg (or 3%). To achieve this, the subjects consumed on average three muffins or about an extra 750 kcals/day.

However, where the excess calories went was quite different.

While the subjects eating saturated fat markedly increased their liver fat and gained almost twice as much visceral fat as those in the poly-unsaturated fat group, the latter experienced a nearly three-fold larger increase in lean tissue than the saturated fat group.

The two diets also had quite different effects on the expression of genes regulating energy dissipation, insulin resistance, body composition and fat cell differentiation in subcutaneous fat tissue.

Thus, the authors conclude that while overeating saturated fat promotes liver and visceral fat storage, the excess energy from poly-unsaturated fat may instead promote the growth of lean tissue.

What I learnt from this study is that there are indeed important differences in how the body handles excess calories depending on where they come from.

In that respect at least, not all calories are equal.

@DrSharma
Edmonton, AB

Fat Jokes Are Not Funny! Help publish this anti-bullying children’s book

ResearchBlogging.orgRosqvist F, Iggman D, Kullberg J, Jonathan Cedernaes J, Johansson HE, Larsson A, Johansson L, Ahlström H, Arner P, Dahlman I, & Risérus U (2014). Overfeeding Polyunsaturated and Saturated Fat Causes Distinct Effects on Liver and Visceral Fat Accumulation in Humans. Diabetes PMID: 24550191

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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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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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