We all know that BMI is not a good measure of body fat. In fact, all anthropometric measurements (waist circumference, skin-fold thickness, etc.) have important limitations when applied to individuals.
Currently, the two most common clinical approaches to measuring body composition are measuring bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA).
But just how practical and reliable are these methods in clinical or research settings when applied to individuals with higher BMI levels?
This is the subject of a review article by Carlene Johnson Stoklossa and colleagues from the University of Alberta, published in Current Obesity Reports.
The researchers looked at 12 studies that applied these methods to individuals with a BMI of 35 or greater.
Largely because of its sensitivity to fluid balance, BIA overestimated fat-free mass with scaling errors as BMI increased.
In contrast, DXA provided accurate and reliable body composition measures, but equipment-related barriers prevented assessment of some taller, wider, and heavier subjects.
From these findings, the authors conclude that BIA must be regarded as a largely unreliable method to assess body composition in individuals with class II/III obesity.
In contrast, DXA, although reliable, will likely need some technological improvements that will allow more inclusive testing of taller and larger individuals.
What exactly, clinicians are to do with this information or how such measurements can potentially improve obesity care remains to be determined.
However, for many dietitians, keeping up to date with the many issues related to obesity – from our evolving understanding of the complex neurobiology of energy homeostasis that make obesity a chronic disease to the issues of emerging pharmacotherapy and nutritional care for the bariatric surgery patient – is always a challenge.
This is why the Canadian Obesity Network has partnered with Dietitians Canada to, for the 6th time, to bring you this popular intensive course on obesity management (exclusively for dietitians only).
Those, who have attended this course before may wish to attend again – those who have not, you are in for a course that is guaranteed to change your practice.
For more information on this retreat (limited spots open) – click HERE
To see the final program – click HERE
To register – click HERE
Every 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!
There is no doubt that exercise is good for you and that individuals with obesity, both before and after bariatric surgery (like everyone else), would stand to benefit from increasing their levels of physical activity.
Following bariatric surgery, exercise may be particularly important not just to increase physical fitness, but also to limit the obligatory loss in muscle mass that generally accompanies weight loss.
Now, a study by David Creel and colleagues, published in OBESITY, compares three levels of exercise intervention in patients following bariatric surgery in terms of effectiveness and adherence.
A total of 150 patients undergoing bariatric surgery were randomised to either standard care (SC), pedometer use (P), or exercise counseling group (C).
The standard care group (SC) received no exercise support by the bariatric center beyond a simple educational pamphlet.
Participants in the pedometer group (P) were given a pedometer and a one-page information sheet on using the device to increase physical activity. This handout promoted the progressive attainment of 10,000 steps/day. Individuals were asked to wear their device daily and record date, steps achieved, and whether they wore the device the entire day, part of the day, or not at all. Journals were collected, but no feedback was provided.
Participants in the exercise counselling group (C) were regularly seen at the bariatric centre and counselled by a certified exercise professional using motivational intervention techniques with individual goal setting.
Based on physical activity measurements using an accelerometer over two weeks before and 2, 4, and 6 months postoperatively, there was no difference between the SC and P groups, with a statistically significant but modest increase in daily steps in the C group that emerged at 4 months and was maintained at 6 months (about 1,000 extra steps per day compared to SC).
There was no notable difference in exercise tolerance, which increased in all three groups post surgery.
No group reached the 10,000 steps/day or 150 bout-minutes/week recommended for general health
As may be expected from these rather modest results, no significant differences in weight or weight change were found between groups at any time point.
Thus, these findings suggest that handing out a pedometer and asking patients to journal their activity is no more effective in promoting physical activity, than simply handing out a pamphlet; moreover, even adding in counselling by an exercise professional adds little (if anything) to the outcome.
Although the researchers discuss the possibility that an even more intense intervention may provide more benefit, the modest findings certainly question the effectiveness of activity interventions post surgery.
Certainly, simply handing out pedometers does nothing, and adding in expensive group meetings or meetings with exercise professionals adds little more.
These finding by no means speak against the value of exercise after bariatric surgery – they just speak against the indiscriminate use of expensive healthcare resources, when they achieve little more than can be achieved by handing out a pamphlet.
Now a paper by James Mitchell and colleagues, published in JAMA Surgery, reports on the postoperative eating behaviors and weight control strategies that are associated with differences in body weight seen at 3 years after bariatric surgery.
The study looks at self-reported data from over 2000 participants in the The Longitudinal Assessment of Bariatric Surgery-2 (LABS-2) study, a multicenter observational cohort study at 10 US hospitals in 6 geographically diverse clinical centers in the USA. Participants completed detailed surveys regarding eating and weight control behaviors prior to surgery and then annually after surgery for 3 years.
The researchers assessed 25 postoperative behaviors related to eating, weight control practices, and the use of alcohol, smoking, and illegal drugs.
The three key behaviours associated with poor outcomes were lack of weekly self-weighing, continuing to eat when feeling full more than once a week, and eating continuously during the day.
Thus, a participant who postoperatively started to self-weigh regularly, stopped eating when feeling full, and stopped eating continuously during the day after surgery would be predicted to lose almost 40% of their baseline weight compared to only 24% weight loss in participants who did not adopt these behaviours.
Other behaviours that had negative influences on outcomes included problematic use of alcohol, smoking and illegal drugs.
Thus, as one may have suspected all along, helping patients adopt and adhere to behavioural changes that include self-montioring and mindful eating behaviours can be expected to substantially affect the success of bariatric surgery.
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