Dr. Sharma's Obesity Notes

Prof. Bente Klarlund Pedersen, University of Copenhagen

This week, I am attending the 20th European Congress on Obesity in Liverpool.

The opening plenary lecture this morning was presented by Bente Pedersen from the University of Copenhagen, who reviewed her work demonstrating that the profound positive effects of exercise on metabolism, inflammation, mood and cognitive function are mediated by 100s of proteins secreted from skeletal muscle cells in response to muscle contraction.

These molecules are now referred to as “myokines” and have been shown to exert either autocrine, paracrine or endocrine effects on other organs like adipose tissue, liver, pancreas, bones and brain..

This exciting area of research is nicely summarized in a recent paper by Bente Pedersen and Mark Febbraio published in Nature Endocrine Reviews.

For example, exercise-induced increases in myocellular production of BDNF and IL-6 can increase AMPK-mediated fat oxidation, whereby IL-6 appears to have systemic effects on the liver, adipose tissue and the immune system and even mediates crosstalk between intestinal L cells and pancreatic islets.

Other myokines (e.g. the osteogenic factors IGF-1 and FGF-2; FSTL-1) can improve the endothelial function of the vascular system.

More recently, the myokine irisin, has been shown to promote “browning” of adipose tissue.

Other lines of research suggest that myokines can influence the growth of cancer cells as well as modulate immune function, bone development and pancreatic B-cells.

Current research using proteomic techniques will likely provide further insights into the hundreds of molecules secreted from skeletal muscle in response to physical activity and explain how these myokines mediate the wide-ranging beneficial effects of exercise and the detrimental effects of sedentariness on many chronic diseases.

AMS

Liverpool, UK

You can follow live tweets from the conference at #ECO2013

Yesterday, we met Mark (as a prototypical representative of the National Weight Control Registry), who, deciding that enough was enough, managed to turn his weight around with a self-directed regimen of eating less and moving more (ELMM).

Today, we meet Julie (whose story I also made up), another prototypical weight-loss maintainer, who believes most vehemently in the power of exercise for weight control.

According to Lorraine Ogden’s paper published in OBESITY, Julie, is part of the largest cluster, which makes up just over half of all National Weight Control Registry participants.

Julie, is 48 years old, married, works full-time as a business executive, has two teenage children and has managed to maintain a weight loss of 62 lbs over the last six years, with remarkably little fluctuation.

Her current BMI is down to 23 from a high of 34.

She has always been relatively healthy, even at her highest weight.

She began gaining weight in high school and reports her mother as also being slightly overweight.

Over the years, Julie had made several previous weight-loss attempts with commercial programs but she does not attribute her current success to any specific program or contact with a health professional.

Rather, her “secret” formula is a rather impressive amount of exercise, easily expending almost 3000 Cal per week in 90 minutes or more of daily ardous exertion.

Apart from her daily runs and/or rides on her bike, she teaches a weekly Zumba class at the local YMCA and simply cannot emphasize enough how physical activity (which she now loves more than anything else) has changed her life.

Although, this rigorous exercise regimen is supported by weighing herself regularly, only keeping healthy foods around the house, and strictly limiting her caloric intake to below 1400 calories, it is ultimately the exercise that Julie believes is her “key” to success.

She is currently very happy with her weight, reports her mood as good and her stress levels as manageable.

Julie, is the dream of the fitness and sports utility industrial complex. She and her cluster mates are the ones most likely to have taken up a serious regimen of activity that now rules their lives.

It is therefore not surprising to learn that Julie is currently training for her second triathlon and wants to get in at least two marathons this year. This Summer vacation will be a visit to France, where she hopes to complete four segments of the Tour de France. For next year, she is contemplating riding her bike from Sacramento to Seattle to raise money for Breast Cancer research.

We all know people like Julie – their determination and drive is unparalleled and awe-inspiring – and, they are somewhat hard to be around (unless of course you happen to share their passion for physical activity).

The Julies that I have personally met, are surprisingly often also foodies – indeed, most things appear to somehow revolve around physical activity and food – the more intense and wholesome, respectively, the better – good for them!

I do not see a lot of Julies in my practice (at least not as patients) – they don’t need me – they are no doubt happier with their personal coaches, sport buddies and farmer markets.

Indeed, should Julie ever need the services of a doctor, it will more likely be from an orthopaedic surgeon than a bariatrician.

If you know of a Julie or perhaps happen to be a Julie yourself, I’d love to hear your story.

AMS
Comox, BC
Ogden LG, Stroebele N, Wyatt HR, Catenacci VA, Peters JC, Stuht J, Wing RR, & Hill JO (2012). Cluster analysis of the national weight control registry to identify distinct subgroups maintaining successful weight loss. Obesity (Silver Spring, Md.), 20 (10), 2039-47 PMID: 22469954

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Few events are likely to command your attention as urgently as a sudden interruption of blood flow to your heart muscle.

Fortunately, thanks to the miracle of modern cardiac revascularization, you may well find yourself amongst the many, who today survive this “heart-wrenching” event – a situation which often precipitates remarkably intense longings for lifestyle change.

Indeed, at no time (other than January 1), would you meet anyone more determined to swear off their cigarettes, convert to the solemn teachings of Canada’s Food Guide and embrace the rejuvenating powers of exercise – an only fitting response to celebrate this new lease on life.

This is why many modern health systems dedicate a significant amount of personnel and resources to the exploitation of this life-changing moment with the laudable goal of “re-habilitating” the fortunate survivor to a life of healthier habits.

But, you may ask, is even such a dramatic event enough to prompt lasting betterment in the victims? And, will those, who have brought this upon themselves through their supposedly unholy practice of gluttony and sloth, really manage to turn things around?

This burning question has now been thoroughly examined by Billie-Jean Martin (a former Obesity Network Bootcamper) and colleagues from the University of Calgary, in a paper published in OBESITY.

Happily enough, almost 4,000 participants, studied one year after their participation in a 12-week rehabilitation program (which invoked the dedicated services of exercise physiologists, nurses, registered dieticians, social workers and clinical psychologists), did indeed experience a small but measurable improvement in aerobic fitness – a parameter known to forecast survival.

Sadly, however, not everyone benefitted equally. Despite enthusiastic participation in the program, obese patients (who also happened to start off on a poorer footing in terms of exercise capacity) showed a lesser sustained improvement in peak estimated metabolic equivalents (a sciency measure of aerobic fitness) than their less corpulent counterparts.

Prejudiced readers should, however, not jump to the conclusion that the obese participants were perhaps less enthusiastic or committed to this enterprise.

Indeed, during the 12 week intervention, the obese group increased their weekly mins at the prescribed exercise heart rate by 40 mins (from 123 to 163), whereas their leaner peers merely managed to add a measly 10 mins to their routine (from 153 to 164). Clearly, the obese participants were not shying away from the extra effort – if anything, they were working substantially harder (relatively speaking) than their leaner colleagues.

Notably, at one year, BOTH groups had regressed in their enthusiasm to slightly BELOW their baseline weekly mins of exercise heart rates; the obese group fell back to 121 mins, while the normal weight group fell back to 150 mins.

Thus, to be fair, NEITHER group managed to sustain the recommended 160+ mins of weekly exercise heart rate at 12 months.

It would seem that neither the “life-changing” occurrence of clogged coronaries nor 12 weeks of the dedicated services of an inter-disciplinary team of healthcare professionals, appears to be all that life-changing after all.

Would a 16 week program, a 24 week program, or perhaps even a 52 week program have lead to better results?

My gut tells me that any “time-limited” behavioural-change program will always produce “time-limited” behavioural change.

Apparently, the situation for cardiac rehab appears no better than the story for weight loss – when “treatment” stops, the lifestyle/weight comes back.

Incidentally, the Albertan actors in this story are no better or worse than the rest of Canada.

According to a recent report from Statistics Canada, three in four smokers with respiratory disease do not quit smoking; most people with diabetes or heart disease will not become more physically active and virtually no one diagnosed with cancer, heart disease, diabetes or stroke will increase their intake of fruit and vegetables.

Nonetheless, I am told, cardiac rehab efforts have demonstrated benefits in a host of modifiable cardiovascular risk factors, at least during and perhaps for a few months following the intervention.

However, the durability of these efforts certainly leave substantial room for improvement across the full spectrum of body shapes and sizes.

AMS
Edmonton, AB

Martin BJ, Aggarwal SG, Stone JA, Hauer T, Austford LD, Knudtson M, & Arena R (2012). Obesity negatively impacts aerobic capacity improvements both acutely and 1-year following cardiac rehabilitation. Obesity (Silver Spring, Md.), 20 (12), 2377-83 PMID: 22627915

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in 2004, we published a paper in the Journal of Cardiopulmonary Rehabilitation, in which we looked at the relationship between metabolic profiles and exercise capacity in overweight and obese patients participating in an outpatient cardiac rehabilitation program.

our retrospective analysis of cross-sectional data for 3542 patients, ages 63 +/- 11 years, showed that 81% of the patients had a BMI exceeding 25, and that 35% of the patients were obese (BMI > 30).

After adjustment for age, sex, smoking, hypertension, diabetes, and peak power output, BMI remained a significant independent predictor of a higher total cholesterol level, higher fasting blood glucose and triglyceride levels, and lower levels of high-density lipoprotein cholesterol.

Based on the Adult Treatment Panel III criteria, 77% of the obese males in classes 2 and 3 had three or more risk factors for the metabolic syndrome, as compared with 68% of the obese females in this obesity BMI class.

After 24 weeks of intervention, the outcome data (available for 1353 patients) showed that despite no change in body weight, all the BMI groups demonstrated significant improvements in metabolic profiles and peak exercise capacity.

This study clearly shows that cardiac rehabilitation results in significant improvement in the cardiovascular risk profile at all levels of BMI, independently of weight loss.

What and how much weight loss would add to these outcomes clearly has yet to be demonstrated.

Given that, by definition, all of the obese patients in this study would be considered to have at least Edmonton Obesity Stage 3 obesity, we clearly find that benefits from increasing exercise capacity and improving diet can improve metabolic parameters even if little weight is lost.

This does not mean that losing weight may not have additional benefits – it just shows that just because your patient is not losing weight, doesn’t mean they’re not getting healthier.

AMS
Cambridge, UK

Over the next little while, I will be taking a few days off and so I will be reposting some of my favourite past posts. The following article was first posted on Dec 2, 2009:

According to a paper by Malachy McHugh from the Nicholas Institute of Sports Medicine and Athletic Trauma, Lenox Hill Hospital, US, published in the latest issue of the British Journal of Sports Medicine, overweight and obese adolescents are more than twice as likely to be injured in sports and other physical activities compared with non-overweight and non-obese adolescents. Moreover, obese adolescent athletes are more than three times as likely to sustain an ankle sprain compared with normal weight adolescent athletes.

The increased risk of injury associated with being overweight or obese may in part be due to low physical activity levels and therefore promotion of physical activity for children can provide neuromuscular training that may be beneficial in decreasing injury risk associated with general play and sports. In addition, specific neuromuscular training interventions, such as balance training, may also help reduce the risk of injury associated with overweight and obesity.

Importantly, injured overweight young athletes tend to have more prolonged recovery periods than non-overweight young athletes.

According to McHugh, early aggressive treatment of swelling with physical modalities, prolonged non-weight bearing, limited period of immobilization, and regular repetitive passive joint motion are all indicated for the overweight young athlete with a lower extremity joint injury.

AMS
Frankfurt, Germany