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Cold Exposure Promotes Gut Microbes That Stimulate Brown Fat

It seems that there is no end to how intimately gut microbes are linked to metabolic function. Thus, a study by Claire Chevalier and colleagues from Geneva, Switzerland, published in CELL, not only shows that cold exposure (of mice) changes their gut microbes but also that, when transplanted into sterile mice, these “cold” microbes stimulate the formation of thermogenic brown fat. All of this makes evolutionary sense, as the increase in heat-generating (and calorie-burning) brown fat with cold exposure would protect the organism against cold exposure – however, that gut bacteria would be involved in this process is indeed rather surprising. Unfortunately, at least for those thinking that “cold bacteria” may be the panacea for stimulating brown fat and thus weight loss are likely to be disappointed. The researchers also show that with prolonged exposure to cold, these “cold bacteria” induce changes to the structure and function of the gut that enable more glucose to be absorbed. While in the short-term, this extra fuel can be used by the brown fat to generate heat, in the long-term, some of these extra calories probably go towards building more white fat and thus weight gain. Again, this makes evolutionary sense. After all, it is ecologically a far better strategy to insulate the house than to waste extra calories heating it. This is why, the naive notion that simply lowering ambient temperature as a means to generate more brown fat and thus, burn more calories, may not be all that effective. Indeed, these experiments suggest rather that chronic cold exposure would ultimately stimulate extra insulation, i.e. more subcutaneous fat and weight gain. Funnily enough, these findings turn the hypothesis that reducing room temperature would promote weight loss into exactly the opposite. Perhaps it is the excessive use of air-conditioning to generate freezing indoor temperatures (as any European visitor to the US will readily attest to), is part of the problem. Fascinating stuff for sure. @DrSharma Gurgaon, Haryana

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Just How Much Weight Do You Gain When You Stop Smoking?

The fact that smoking cessation is almost regularly associated with weight gain is common knowledge. But just how much weight can one expect to gain? Now,  an analysis from a large randomised controlled trial of smoking cessation by Charles Courtemanche and colleagues published for the National Bureau of Economic Research, that this weight gain may be more that most people think. The researchers look at data from well over 5,000 participants in the Lung Health Study. Using various statistical models, they conclude that the average weight gain is about 12 pounds, with the effect being greatest in the young, women and those starting out with a ‘normal’ weight. They also calculate that the reduction in smoking over the past decades accounts for about 15% of the obesity epidemic. From the longitudinal analysis they also conclude that the weight gain is not temporary nor likely reversible. If anything, the impact of smoking cessation on weight becomes greater as time passes. Thus, while the authors remind us that the benefits of smoking cessation on health still by far outweigh any health detriments from a 12 lb weight gain. Nevertheless, the data should remind us that smoking cessations efforts should always go hand in hand with efforts to prevent excessive weight gain. @DrSharma Gurgaon, Haryana  

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The Lancet Commission On Obesity – A Global Approach To Globesity?

Obesity is a global problem – no country appears immune – the global direct and indirect costs in human and social costs are in the trillions. Thus, The Lancet should no doubt be commended on partnering with the World Obesity Federation to constitute an international panel of 22 experts under the leadership of Boyd Swinburn (New Zealand) and William Dietz (USA) to “…stimulate action on obesity and strengthen accountability systems for the implementation of agreed recommendations to reduce obesity and its related inequalities and to develop new understandings of the underlying systems that are driving obesity in order to develop innovative approaches towards making those systems less obesogenic.“ While (perhaps to my surprise) I have previously heard of only one of the panelists (Shiriki Kumanyika, Emeritus Professor of Biostatistics and Epidemiology, University of Pennsylvania), I am sure that all of the panelists bring a wide range of expertise to the table. The overall mandate of the Commission is rather ambitious, with the following declared goals: First, the Commission will stimulate action and strengthen accountability systems for the implementation of agreed recommendations to reduce obesity and its related inequalities at global and national levels. Second, it will develop new understandings of the underlying systems that are driving obesity and also devise innovative approaches to reorient those systems in a sustainable and scalable way to encourage healthy weight. Third, it will also establish mechanisms for regular, independent reporting on progress towards national and global obesity targets, implementation of recommended policies and actions, and specific systems analyses of obesity drivers and solutions. Clearly, the Commission has its work cut out for it, as their goal is to address all underlying systems that are driving obesity, including nutrition, physical activity, urban planning, food systems, agriculture, climate change, economics, governance and politics, law, business, marketing and communication, trade and investment, human rights, equity, systems science, consumer advocacy, monitoring and evaluation, Indigenous health, epidemiology, medicine, and health care. The Commission will have its inaugural meeting in February, 2016, in Washington DC, USA, to determine its work plans. I guess we should stay tuned to see exactly what that plan will look like. @DrSharma Edmonton, AB

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Leaders Have To Understand, Accommodate, Embrace & Support Diversity

Earlier this week, I spoke at a leadership lecture series on barriers to participation at the Peter Lougheed Leadership College at the University of Alberta. The speaker series was hosted by the principal of the college,the Right Honourable Kim Campbell, who served as Canada’s 19th prime minister in 1993. While I spoke about the particular challenges and barriers faced by Canadians living with obesity and how these can be accommodated and supported in the workplace and society in general, other speakers spoke on the accommodation of individuals living with other challenges. Thus, Kelly Falardeau, herself a victim and advocate for burn survivors and Deryk Beal, one of Canada’s  leading clinician scientists on stuttering and other speech impediments, joined me in speaking on the importance of diversity and the need to identify obstacles to social inclusion that keep individuals from reaching their full potential. In my presentation I did my best to portray the biological, physical, emotional and societal challenges that Canadians living with obesity face everyday. Here is what I asked the students to think about: “So how can we help people living with such barriers? For one, let us educate ourselves on the real issues – if there was an easy solution that actually worked, believe me my clinic would be empty. Secondly, let us show some respect for people who wake up with this barrier every single morning and go through their day – for the most part doing everything everyone else does.  Thirdly, let us acknowledge that once you have obesity there is no easy way back. I have patients who have lost their entire weight over on diet after diet after diet only to put the weight back again. Diet and exercise is simply not enough for most people – surgery works but is not available and not scalable – we cannot do surgery on 120,000 Albertans. So let us not pretend that there is an easy solution to the problem – we simply don’t have enough treatments that work. Fourthly, till we do come up with more treatments that actually work or maybe even get our act together on prevention, let us not make life harder for people living with this barrier than it has to be. We can do many things to accommodate people living with obesity – we accommodate people with all kinds of “special needs” at home, in society in the workplace –… Read More »

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The Role of Social Norms In Eating Behaviour

Eating is often a social activity and there is no doubt that social settings have a tremendous impact on when, what and how we eat. Now Suzanne Higgs and Jason Thomas from the University of Birmingham, UK, in a paper published in Current Opinion in Behavioral Science review the role of social norms in eating behaviours and discuss how these norms could potentially be targeted to improve eating behaviours. “We eat differently when we are with other people compared with when we eat alone. Our dietary choices also tend to converge with those of our close social connections. One reason for this is that conforming to the behaviour of others is adaptive and we find it rewarding. Norms of appropriate eating are set by the behaviour of other people, but also shared cultural expectations and environmental cues. We are more likely to follow an eating norm if it is perceived to be relevant based on social comparison. Relevant norms are set by similar others and those with whom we identify… Norm matching involves processes such as synchronisation of eating actions, consumption monitoring and altered food preferences.” “Social norms may have had a role to play in recent rises in obesity by reinforcing new behaviour patterns associated with overeating and weight gain. For example, increases in average portion size may have created new consumption norms that are diffused through social networks. It might also be that the social context of eating has changed recently in ways that favour overconsumption. For example, more people eating away from home in fast food restaurants with others might be associated with social facilitation of eating.” If, how and to what extent, eating culture can be changed at a population level through public health and policy interventions will certainly remain the subject of further study. @DrSharma Frankfurt, Germany

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