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.
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 – just not for people living with obesity.
Fifth, let us show our support for people who struggle with their weight by the way we treat them, the way we talk about them, the way we engage with them – they are people like all of us. Just because they carry extra weight does not mean they are second class citizens or people we can simply make fun of or ignore – we are after all talking about 7 million Canadians – men, women and children.
Let us not be the barrier that makes their life even more difficult than it already is.”
Our presentations were followed by an enthusiastic ‘master class’ with students in the inaugural leadership class of the Peter Lougheed Leadership College.
I’d like to thank the organizers for giving me the opportunity to advocate on behalf of Canadians living with obesity.
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.
To students of human physiology, the commonly held view that obesity is simply a matter of energy in and energy out is nothing short of laughable.
Indeed, there are perhaps no other biological functions of more importance for survival of an organism, than those that regulate energy uptake, storage and expenditure – functions, without any form of life would be impossible.
Thus, the finely tuned complex and often highly redundant pathways that have evolved to optimize energy metabolism have evolved to readily switch from states of feeding to starvation with shifts in substrate use (both qualitative and quantitative) – functions that are controlled by hundreds (if not thousands) of genes.
Getting these genes to work in concert, requires a complex system of gene regulation, by which individual genes are switched on an off (to allow or stop protein synthesis) in various tissues to just the right amount at just the right time – a process known as transcriptional control.
Now, a comprehensive review by Adelheid Lempradl and colleagues, published in Nature Genetics, summarizes the multitude of interlinked processes that control transcription of genes involved in energy homeostasis.
As the authors explain,
“Transcriptional control is the sum of the cellular events that select and dose gene transcription. In simple terms, these events converge on the regulation of gene locus accessibility and polymerase activity (including recruitment, pausing, processivity and termination).”
“Energy homeostasis requires multi-layered regulation via dynamic, often periodic, expression of metabolic pathways to properly anticipate and respond to shifts in energy state.”
“Transcription factors act by binding to specific regulatory DNA sequences, thus controlling the transcriptional output of defined target gene sets. They cooperate with co-regulators, which either promote (co-activators) or inhibit (co-repressors) transcription. Together, they build feedback networks and control the stability and responsiveness of energy homeostasis. Metabolic cells use receptors and metabolic machinery to generate specific signalling responses to endocrine inputs (for example, insulin, glucagon or leptin receptors) or metabolic inputs (for example, the primary energy metabolism machinery itself).”
The papers goes on to discuss at length the various regulator, co-regulators and the plethora of epigenetic modifiers that determine how these factors do their job of activating or deactivating relevant genes throughout the body.
Why is any of this important?
“Rapid progress is currently being made in research on chromatin-based regulation of gene expression. Particular unknowns include the mechanisms that establish long-term set points or priming of gene expression. Identifying the processes that establish activation thresholds and maximal output set points, as well as their self-organizing principles is currently an intriguing area of research, and is important in understanding susceptibility to complex trait disorders, including metabolic and autoimmune diseases. For example, many intergenerational and developmental reprogramming paradigms elicit metabolic disease susceptibility. They highlight the potential impact of subtly divergent transcriptional profiles in any given genetic context.”
In other words, understanding these processes are fundamental for our understanding of everything from the body’s weight set point (and how this is altered) to intergenerational transmission of obesity risk from one generation to the next (perhaps the most important driver of the current obesity epidemic).
But the complexity of these processes also raise important issues for clinicians,
“The seemingly exponential growth in this complexity now poses a major challenge for translational researchers in need of simplified but accurate paradigms for clinical use.”
The least we can do is to stop pretending that there is anything easy about energy in and energy out.
Now, an interesting paper by Charles Spence and colleagues from Oxford University, published in Brain and Cognition, makes a strong case for how exposure to images of desirable foods (which they label ‘food porn’, or ‘gastroporn’) via digital interfaces might be inadvertently exacerbating our desire for food (what they call ‘visual hunger’).
In their paper, the authors review the growing body of cognitive neuroscience research demonstrating the profound effect that viewing such images can have on neural activity, physiological and psychological responses, and visual attention, especially in the ‘hungry’ brain.
Beginning with a brief discussion of evolutionary aspects of vision and food, the authors remind us that,
“Foraging – the search for nutritious foods – is one of the brain’s most important functions. In humans, this activity relies primarily on vision, especially when it comes to finding those foods that we are already familiar with. In fact, it has been suggested that trichromatic colour vision may originally have developed in primates as an adaptation that facilitated the selection of more energy-rich (and likely red) fruits from in-amongst the dark green forest canopy.”
“The brain is the body’s most energy-consuming organ, accounting for somewhere in the region of 25% of blood flow, or rather, 25% of the available consumed energy. Note that this figure is even higher in the newborn human, where the brain absorbs up to two thirds of the energy that is consumed by the developing organism. As Brown notes: “In embryos, the first part of the neocortex to develop is the part which will represent the mouth and tongue…” As the brain grew in size over the course of human evolution, the demands on the visual system to efficiently locate nutrients in the environment would likely also have increased.”
This notion is not trivial given our current environmental exposure to a multitude of food images:
“Our brains learnt to enjoy seeing food, since it would likely precede consumption. The automatic reward associated with the sight of food likely meant another day of sufficient nutrients for survival, and at the same time, the physiological responses would prepare our bodies to receive that food. Our suggestion here is that the regular exposure to virtual foods nowadays, and the array of neural, physiological, and behavioural responses linked to it, might be exacerbating our physiological hunger way too often. Such visual hunger is presumably also part of the reason why various food media have become increasingly successful in this, the digital age.”
And the influence of food media is widespread:
“Every day, it feels as though we are being exposed to ever more appetizing (and typically high calorie) images of food, what some (perhaps pejoratively) call ‘gastroporn’ or ‘food porn’. Moreover, the shelves of the bookstores are increasingly sagging under the weight of all those cookbooks filled with high-definition and digitally-enhanced food images. It has been suggested that those of us currently living in the Western world are watching more cookery shows on TV than ever before. Such food shows often glamorize food without necessarily telling a balanced story when it comes to the societal, health, and environmental consequences of excess consumption.”
And let’s not forget facebook and Instagram:
“At the same time, the last few years have seen a dramatic rise in the dining public’s obsession with taking images of the foods that they are about to eat, often sharing those images via their social media networks. The situation has reached the point now that some chefs are considering whether to limit, or even, on occasion, to ban their customers from taking photographs of the dishes when they emerge from the kitchen. However, one restaurant consultant and publisher has recently suggested that the way food looks is perhaps more important than ever: “I’m sure some restaurants are preparing food now that is going to look good on Instagram”.
The paper goes on to discuss at length the evidence that exposure to images of foods can alter cognitive responses and create the need for constant dietary restraint, which may be more difficult for some than others.
But not all images of food have these effects:
“These results support the view that people rapidly process (i.e. within a few hundred milliseconds) the fat/carbohydrate/energy value or, perhaps more generally, the pleasantness of food. Potentially as a result of high fat/high carbohydrate food items being more pleasant and thus having a higher incentive value, it seems as though seeing these foods results in a response readiness, or an overall alerting effect, in the human brain.”
As for the parts of the brain that are stimulated by exposure to food images – pretty much all of it. Thus, in one study:
“…the results revealed that obese individuals exhibited a greater increase in neural activation in response to food as compared to non-food images, especially for high-calorie foods, in those brain regions that are associated with reward processing (e.g., the insula and OFC), reinforcement and adaptive learning (the amygdala, putamen, and OFC), emotional processing (the insula, amygdala, and cingulate gyrus), recollective and working memory (the amygdala, hippocampus, thalamus, posterior cingulate cortex, and caudate), executive functioning (the prefrontal cortex (PFC), caudate, and cingulate gyrus), decision making (the OFC, PFC, and thalamus), visual processing (the thalamus and fusiform gyrus), and motor learning and coordination, such as hand-to-mouth movements and swallowing (the insula, putamen, thalamus, and caudate).”
But this knowledge is not all bad. There is also some evidence that digital manipulation of images of vegetables and other healthy foods can make them more attractive and thus hopefully increase their consumption. Whether or not this would actually work in practice remains to be seen.
“Given the essential role that food plays in helping us to live long and healthy lives, one of the key challenges outlined here concerns the extent to which our food-seeking sensory systems/biology, which evolved in pre-technological and food-scarce environments, are capable of adapting to a rapidly-changing (sometimes abundant) food landscape, in which technology plays a crucial role in informing our (conscious and automatic) decisions.”
Are you affected by exposure to foodporn? Is this really a problem?
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