Following the recent release of the Canadian Task Force on Preventive Health Care guidelines for prevention and management of adult obesity in primary care, the Task Force yesterday issued guidelines on the prevention and management of childhood obesity in the Canadian Medical Association Journal (CMAJ).
Key recommendations include:
- For children and youth of all ages the Task Force recommends growth monitoring at appropriate primary care visits using the World Health Organization Growth Charts for Canada.
- For children and youth who are overweight or obese, the Task Force recommends that primary health care practitioners offer or refer to formal, structured behavioural interventions aimed at weight loss.
- For children who are overweight or obese, the Task Force recommends that primary health care practitioners not routinely offer Orlistat or refer to surgical interventions aimed at weight loss.
The lack of enthusiasm for the prevention of childhood obesity is perhaps understandable as the authors note that,
“The quality of evidence for obesity prevention in primary care settings is weak, with interventions showing only modest benefits to BMI in studies of mixed-weight populations, with no evidence of long-term effectiveness.”
leading the Task Force to the following statement,
“We recommend that primary care practitioners not routinely offer structured interventions aimed at preventing overweight and obesity in healthy-weight children and youth aged 17 years and younger. (Weak recommendation; very low-quality evidence)”
Be that as it may, the Task Force does recommend structured behavioural interventions for kids who already carry excess weight based on the finding that,
“Behavioural interventions have shown short-term effectiveness in reducing BMI in overweight or obese children and youth, and are the preferred option, because the benefit-to-harm ratio appears more favourable than for pharmacologic interventions.”
What caught my eye however, was the statement in the accompanying press release which says that,
“Unlike pharmacological treatments that can have adverse effects, such as gastrointestinal problems, behavioural interventions carry no identifiable risks.” (emphasis mine)
While I would certainly not argue for the routine use of orlistat (the only currently available prescription drug for obesity in Canada) in children (or anyone else), I do take exception to the notion that behavioural interventions carry no identifiable risks – they very much do.
As readers may be well aware, a large proportion of the adverse effects of medications is attributable to the wrong use of these medications – problems often occur when they are taken for the wrong indication, at the wrong dose (too high or too low), the wrong frequency (too often or too seldom), and/or when patients are not regularly monitored. In a perfect world, many medications that often lead to problems would be far less problematic than they are in the real world.
Interestingly, the same applies to behavioural interventions.
Take for example diets – simply asking a patient to “eat less” can potentially lead to all kinds of health problems from patients drastically reducing protein, vitamin and mineral intake as a result of going on the next “fad” or “do-it-yourself” diet. Without ensuring that the patient actually follows a prudent diet and does not “overdo” it, which may well require ongoing monitoring, there is very real potential of patients harming themselves. There is also the real danger of promoting an eating disorder or having patients face the negative psychological consequences of yet another “failed” weight-loss diet. Exactly how many patients are harmed by well-meant dietary recommendations is unknown, as I am not aware of any studies that have actually looked at this.
The same can be said for exercise – simply asking a patient to “move more” can result in injury (both short and long-term) and coronary events (in high-risk patients). Again, ongoing guidance and monitoring can do much to reduce this potential harm.
In short when patient apply behavioural recommendations at the wrong dose (too much or too less), wrong frequency (too often or too seldom), and/or are not regularly monitored, there is indeed potential for harm – I would imagine that this potential for harm is of particular concern in kids.
This is not to say that we should not use behavioural interventions – we should – but we must always consider the potential for harm, which is never zero.
I’d certainly be interested in hearing from anyone who has seen harm resulting from a behavioural intervention.
Unfortunately, judging by a randomised-controlled trial by Aidon Gribbon and colleagues from the University of Ottawa, published in the American Journal of Clinical Nutrition, this remains but a dream.
For this study, 26 male adolescents were randomised to three 1-hour sessions of rest, seated video game and an active video game. This was each followed by an ad libitum lunch. The researchers also asked the subjects to complete dietary records for another 3 days
Energy expenditure was measured by using portable indirect calorimetry throughout each experimental condition, and an accelerometer was used to assess the subsequent 3-d period.
Although energy expenditure (as measured by indirect calorimetry) was significantly higher during the active game, there was no significant differences in energy balance at 24hrs or 3 days after the end of the game (no surprise here).
Thus, while the researchers did not see any change in appetite or food intake after the active game, they also found no difference in energy balance after 24 hrs.
Thus, the energy expended during the game was apparently fully compensated for, suggesting that active gaming may have a rather modest (if any) effect on energy balance.
As to exactly how this compensation happens – the researchers attribute this to the:
“compensatory adaptation in spontaneous physical activity occurs subsequent to playing Kinect, resulting in no significant differences in net energy expenditure over the course of 24 h. This compensation in PAEE after engaging in AVGs is consistent with results from exercise trials that showed that individuals tend to compensate for physical activity interventions by decreasing subsequent spontaneous physical activity levels”
On a positive note, the authors also did not see an expected increase in caloric intake after the games.
Whether or not active video gaming over time may lead to different effects remains to be seen.
Now, Mary Boggiano and colleagues from the University of Birmingham, Alabama, in a paper published in Appetite, report that using tasty foods as a coping strategy is associated with weight gain.
The study administered the Palatable Eating Motives Scale (PEMS), which assesses eating for coping motives (e.g., to forget about problems, reduce negative feelings), to 192 college students, who were reexamined after two years (with a few measures in between).
Not too surprisingly, PEMS scores predict changes in BMI over two years.
On a positive note, however, the researchers found that PEMS scores (i.e. using food for coping) can change over time and a reduction in PEMS scores was also associated with a lesser weight gain. In overweight subjects, a reduction in PEMS scores was even associated with modest weight loss.
Thus, the authors suggest that interventions aimed specifically at reducing palatable food intake for coping reasons, should help prevent obesity if this motive-type is identified prior to significant weight gain.
Now a study by Benoit Chassaing and colleagues published in NATURE, suggests that dietary emulsifiers may promote weight gain and the metabolic syndrome by altering the composition of intestinal microbes.
The researchers hypothesized that emulsifiers may increase bacterial translocation across intestinal mucosa, thereby promoting local and systemic inflammation as well as affecting the composition of gut bacteria.
Their study in mice show that relatively low concentrations of two commonly used emulsifiers (carboxymethylcellulose and polysorbate-80) can induce low-grade systemic inflammation, weight gain and features of the metabolic syndrome, as well as promote intestinal inflammation in mice susceptible to inflammatory bowel disease.
Importantly, they used germ-free mice and faecal transplants to show that these changes can be induced simply by transferring the gut microbes from emulsifier-treated animals to controls.
As the authors note,
“These results support the emerging concept that perturbed host-microbiota interactions resulting in low-grade inflammation can promote adiposity and its associated metabolic effects. Moreover, they suggest that the broad use of emulsifying agents might be contributing to an increased societal incidence of obesity/metabolic syndrome and other chronic inflammatory diseases.”
While these findings (if replicated in humans) certainly point to the industrial use of food emulsifiers as a potential cause of the global increase in obesity and inflammatory bowel disease, given that these compounds are present in virtually all processed foods, they may well be difficult to avoid.
Guess it’s back to home cooking with raw ingredients.
Today I will be attending a Summit on Weight Bias at the University of Calgary, that will explore the the issue of weight-based discrimination and ways to address this – especially in health care settings.
It should come as no surprise that weight bias and discrimination are a major barrier to providing proper preventive and therapeutic health care due to the widespread attitudes and beliefs about obesity that exist amongst health professionals and decision makers.
The scientific summit, co-sponsored by the Canadian Obesity Network, Campus Alberta, and the Canadian Institutes of Health Research (CIHR), is complemented by a public Cafe Scientifique that will be held on Thursday, March 12, 7.00 at the Parkdale Community Association, 3512 – 5 Ave NW, in Calgary.
For more information and pre-registration for this free public event, which features
Leora Pinhas, MD
Child & Adolescent Psychiatrist, Physician Lead, Eating Disorders Unit, Ontario Shores Centre for Mental Health Sciences Assistant Professor, University of Toronto
Tavis Campbell, PhD
Professor, Department of Psychology and Oncology & Director, Behavioural Medicine Laboratory, University of Calgary
Yoni Freedhoff, MD, CCFP
Medical Director, Bariatric Medical Institute, Assistant Professor, University of Ottawa