Obesity Weekend Roundup, June 27, 2014

As not everyone may have a chance during the week to read every post, here’s a roundup of last week’s posts:

Have a great Sunday! (or what is left of it)

@DrSharma
Vancouver, BC

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Canadians Embark on Landmark Study on Managing Childhood Obesity

sharma-obesity-kids-scale2In line with  global trends, there is considerable concern in Canada on the rising prevalence of childhood obesity.

While much work continues to focus on preventing childhood obesity, far less is known about managing it.

Now, a virtual who-is-who of pediatric obesity researchers and clinicians from across Canada have embarked on a creating the CANadian Pediatric Weight Management Registry (CANPWR), the protocol of which appears in BMC Pediatrics.

CANPWR has three primary aims:

1. To document changes in anthropometric, lifestyle, behavioural, and obesity-related co-morbidities in children enrolled in Canadian pediatric weight management programs over a three-year period;

2. To characterize the individual-, family-, and program-level determinants of change in anthropometric and obesity-related co-morbidities;

3. To examine the individual-, family-, and program-level determinants of program attrition.

This prospective cohort, multi-centre study will include 1,600 children (2 – 17 years old with a BMI >=85th percentile) enrolled in eight Canadian pediatric weight management centres.

Data collection will occur at presentation and 6-, 12-, 24-, and 36-months follow-up.

Although the primary study outcomes are BMI z-score and change in BMI z-score over time a number of secondary outcomes including other anthropometric (e.g., height, waist circumference,), cardiometabolic (e.g., blood pressure, lipid profile, glycemia), lifestyle (e.g., dietary intake, physical activity, sedentary activity), and psychosocial (e.g., health-related quality of life) variables will also be assessed.

The researchers will also examine potential determinants of change and program attrition including individual-, family-, and program-level variables.

I am certain that the findings will be of considerable interest not just in terms of helping us better understand exactly how childhood obesity is being effectively managed in Canada (or not) but also provide important insights for planning future obesity management services for kids with overweight and obesity.

@DrSharma
Vancouver, BC

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Guidelines for Managing Overweight and Obesity in Adults

the obesity societyRegular readers may recall a previous post on guidelines on obesity management released by The Obesity Society (TOS) together with other organisations, including the American Heart Association and the American College of Cardiology, at Obesity Week in Atlanta last year (2013).

The bottom line, as I have blogged before, was the revelation of just how little we actually know about obesity.

For what it is worth, the complete guidelines are now published as a supplement to its July issue of the Obesity journal (Guidelines (2013) for Managing Overweight and Obesity in Adults: Full Report).

According to The Obesity Society’s press release,

TOS is investing in the improved treatment of obesity by making the full guidelines available in print so they can serve as a go-to resource for health practitioners around the world. Whether you are a physician, nurse, nutritionist or fitness trainer, every professional interacting with individuals with obesity can find value in this insightful treatment guide.

No doubt, a tremendous amount of work went into developing these guidelines – whether they will substantially change practice remains to be seen.

@DrSharma
Vancouver, BC

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Social Anxiety As A Deterrent To Physical Activity

sharma-obesity-distored-body-image1Social anxiety, defined as persistent fears of one or more social situations in which the person is exposed to others and expects to be scrutinized, has been reported in as many as one in ten individuals with overweight or obesity.

Now, a paper by Abbas Abdollahi and Mansor Abu Talib, published in Psychology, Health and Medicine, examines the relationship between social anxiety and sedentary behaviour in this population.

The researchers surveyed 207 overweight and obese students (measured heights and weights) using a number of validated instruments to assess social anxiety, sedentariness and body esteem.

As one might expect, social anxiety was associated with lower body esteem and higher sedentary behaviour.

The key mediator in this relationship was body dissatisfaction and poor body esteem.

Thus,

“…obese individuals with poor body esteem are more likely to report social anxiety, because they are concerned about negative evaluation by others; therefore, obese individuals indicate avoidance behaviour, which, ultimately, leads to social anxiety.”

The implications of these findings are obvious,

“First, when assessing the social anxiety in individuals, it is important to account for the presence of sedentary behaviour in addition to other psychological risk factors. Second, reducing sedentary behaviour can alter the effect of social anxiety factors; this may be a significant factor to incorporate into social anxiety treatment programmes. Reducing social anxiety in individuals is a main part of any clinical intervention. Third, the findings of the current study suggest that health professionals should encourage obese individuals with social anxiety to reassure their value and abilities regardless of their weight or body shape, and assist them to recognize that everybody is unique and that differences between individuals are valuable.”

This will take more than simply telling people with overweight to be more active. It will certainly require targeted and professional help to overcome body dissatisfaction and low self esteem.

Or, even better, we need to do all we can to help people gain more confidence and be accepting about their own bodies in the first place.

@DrSharma
Vancouver, BC

ResearchBlogging.orgAbdollahi A, & Talib MA (2014). Sedentary behaviour and social anxiety in obese individuals: the mediating role of body esteem. Psychology, health & medicine, 1-5 PMID: 24922119

 

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Time To Go Nuts About Nuts?

sharma-obesity-nutsNuts are reportedly chock full of all kinds of nutrients and are probably among the healthiest of snacks. However, they are also among the most calorie-dense foods – a small handful of nuts (~30 g) can easily add up to 150-200 cals.

So, do high consumers of nuts run the risk of weight gain?

This issue is discussed in depth by Sze Yen Tan and colleagues in a paper published in the American Journal of Clinical Nutrition, in which they review the effects of nuts on appetite, food intake, metabolism, and body weight.

While eating nuts may not exactly lead to weight loss, most studies find that consumption of “extra” calories as nuts leads to substantially less weight gain than may be expected based on their caloric content.

Their review reflect a number of ways in which nuts may have this effect:

Effect on hunger and appetite:

“…nut ingestion suppresses hunger and desire to eat and promotes fullness. These sensations may aid dietary compensation that offsets much of the energy contributed by nuts. However, strong compensation can also occur independently of reported appetitive effects. This may reflect imprecision in appetite measurement or a truly independent uncharacterized mechanism.”

Mastication (chewing):

“Nuts require considerable oral processing effort and this may, in part, account for the often-noted less-than-predicted effect of their consumption on body weight. The mechanical act of chewing reportedly generates satiation signals through cognitive, neural, endocrine, and physical (eg, gastric emptying) mechanisms; augments cephalic phase responses linked to appetite; influences digestion efficiency; modestly increases energy expenditure; and elicits dietary compensation.”

Nutrient absorption:

“A number of studies have evaluated the efficiency of energy absorption from ground and tree nuts through feeding trials. All showed substantive increases in fecal fat loss with nut consumption, although the values ranged widely from ∼5% to >20%”

Energy expenditure:

“Collectively, there is some evidence that nut consumption increases thermogenesis, but the data are not robust and there is no clear mechanism. One possibility is that the lipid from nuts is absorbed over a prolonged period of time, leading to a small but sustained source of substrate that fuels thermogenesis and could appear as an increase in REE.”

Fat metabolism:

“It has been proposed that nut consumption elevates fat oxidation and preferentially reduces body fat mass, especially in the viscera. These actions are attributed to their high unsaturated fat content….Human studies incorporating different nuts into the diet at realistic doses are needed to determine the effect of nut consumption on body composition.”

With regard to impact on body weight, the authors reach the following conclusions:

Adding nuts to habitual diets:

“Although there are reports of small, but significant increases in body weight with nut consumption, the preponderance of evidence indicates that under controlled or free-living situations, nut consumption does not promote weight gain.”

Eating nuts in calorie-restricted diets:

“The inclusion of nuts in energy-restriction regimens does not impede weight loss. In several trials in which nuts did not augment weight loss, there was a reduction in cardiovascular disease risk indexes in the nut-consuming groups, suggesting that such benefits derive from properties of the nuts rather than just weight change.”

Eating nuts in weight maintenance:

“Several studies assessing the role of nut consumption in weight-maintenance programs have noted a decrease in body weight from baseline. Whether this is due to a greater thermic effect of food or REE effect of the nuts compared with the foods they displaced in the diet has not been established. Nevertheless, current data indicate that the inclusion of nuts in a weight-maintenance program will not lead to weight gain and may aid weight loss.”

Thus, in summary, the authors conclude that,

“…evidence indicates that they pose little challenge to and may even aid weight management. This is attributable to the strong dietary compensation effects they elicit, inefficiency in the absorption of the energy they provide, and possibly an elevation of energy expenditure and fat oxidation.”

As a general caveat to all of these data, it needs to be noted that results varied widely depending on the types of nuts and how exactly these nuts were consumed (e.g. as snacks or added to meals – the former often being more favourable than the latter).

Also, many of the studies had relatively small number of participants and were of rather short duration.

Nevertheless, it does appear that going nuts about nuts may not be quite as detrimental to your weight as their energy content would suggest.

@DrSharma
Toronto, ON

ResearchBlogging.orgTan SY, Dhillon J, & Mattes RD (2014). A review of the effects of nuts on appetite, food intake, metabolism, and body weight. The American journal of clinical nutrition, 100 (Supplement 1) PMID: 24920033

 

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