Over a decade ago, together with over 120 colleagues from across Canada, representing over 30 Canadian Universities and Institutions, I helped found the Canadian Obesity Network with the support of funding from the Canadian National Centres of Excellence Program.
Since then the Canadian Obesity Network has grown into a large and influential organisation, with well over 20,000 professional members and public supporters, with a significant range across Canada and beyond.
During the course of its existence, the Network has organised countless educational events for health professionals, provided training and networking opportunities to a host of young researchers and trainees, developed a suite of obesity management tools (e.g. the 5As of obesity management for adults, kids and during pregnancy), held National Obesity Summits and National Student Meetings. raised funds for obesity research, the list of achievements goes on and on.
Most importantly, the Network has taken on important new roles in public engagement, voicing the needs and concerns of Canadians living with obesity, and advocating for better access to evidence-based prevention and treatments for children and adults across Canada.
To better reflect this expanded mission and vision, the Board of Directors has decided to convert the Canadian Obesity Network into a registered health charity under the new name – Obesity Canada – Obésité Canada.
So with one sad eye, I look back and hope that the Canadian Obesity Network rests in peace – Long Live Obesity Canada!
There is no doubt that some people gain weight when started on anti-depressant medications. However, it is also true that the increased appetite and listlessness that accompanies “atypical” depression can contribute to weight gain. Finally, there is evidence that weight-gain in turn may decrease mood, which in turn may further exacerbate weight gain.
Trying to cut through all of this is a study by Rafael Gafoor and colleagues from King’s College London, in a paper published in BMJ.
They examined data from the UK Clinical Practice Research Datalink, 2004-14, which included data on 136,762 men and 157,957 women with three or more records for body mass index (BMI).
In the year of study entry, 17,803 (13.0%) men and 35,307 (22.4%) women with a mean age of 51.5 years were prescribed anti-depressants.
While during 1, 836,452 person years of follow-up, the incidence of new episodes of ≥5 weight gain in participants not prescribed anti-depressants was 8.1 per 100 person years, it was slightly higher at 11.2 per 100 person years in those prescribed an anti-depressant.
In the second year of treatment the number of participants treated with antidepressants for one year for one additional episode of ≥5% weight gain was 27.
Thus, there appears to be a slight but discernible increased risk of weight gain associated with the prescription of anti-depressants, which may persist over time and appears highest during the second and third year of treatment.
However, as the authors caution, these associations may not be causal, and residual confounding might contribute to overestimation of associations.
Nevertheless, the notion that there may be a distinct weight-promoting pharmacological effect of some anti-depressants is supported by the finding that certain anti-depressants (e.g. mirtazapine) carry a far greater risk of weight gain than others (e.g. paroxetine).
Given the frequency with which anti-depressants are prescribed, it could be argued that the contribution of anti-depressants to the overall obesity epidemic (particularly in adults) may be greater than previously appreciated.
If nothing else, patients prescribed anti-depressants should be carefully monitored for weight gain and preventive measures may need to be instituted early if weight gain becomes noticeable.
While at the level of the individual, clinicians are beginning to acknowledge the vast body of research now showing that “lifestyle” approaches to managing obesity (“eat-less move more”) result in minimal outcomes (3-5% sustainable weight loss at best), public health attempts to address the obesity epidemic continue to perpetuate the myth that obesity (and its prevention) is simply about getting people to eat better and move more (with very little evidence to show that such measures can be implemented at a population level to effect any noticeable change in obesity rates).
In an article I co-authored with Ximena Ramos-Salas, published in Current Obesity Reports, we provide an in-depth overview of current public health policies to address obesity in Canada and argue that the “narrative” underlying these policies is an important driver of weight-bias and discrimination and significantly hindering efforts to provide Canadians living with obesity better access to obesity prevention and treatment efforts.
As we state in the article (based on original research by Ramos-Salas and others),
“A critical review of Canadian obesity prevention policies and strategies revealed five prevailing narratives about obesity: “(1) childhood obesity threatens the health of future generations and must be prevented; (2) obesity can be prevented through healthy eating and physical activity; (3) obesity is an individual behavior problem; (4) achieving a healthy body weight should be a population health target; and (5) obesity is a risk factor for other chronic diseases not a disease in itself”. These narratives create the opportunity for Canadian obesity policy recommendations to focus mainly on individual-based healthy eating and physical activity interventions. By simplifying the causes of obesity as unhealthy eating and lack of physical activity, these policies may be contributing to the belief that obesity can be solely controlled through individual behaviors. This belief is a fundamental driver of weight bias.”
This “world-view” of obesity at the level of policy makers has a significant impact on the willingness and capacity of health systems to provide access to evidence-based obesity treatments to the nearly 7 million Canadian adults and children living with this chronic disease – in fact, the unwillingness to even consider obesity a chronic disease is a big part of the problem.
“..the conceptualization of obesity as a risk factor in public health policies has implications for government action, by prioritizing prevention over treatment strategies and potentially alienating Canadians who already have obesity. The review concludes that existing Canadian public health policies and strategies (a) are not sufficiently comprehensive (i.e., solely focused on prevention and mainly focused on children; exclude evidence-based management approaches; are not person-centered); (b) are based on reductionist obesity models (i.e., models that cast shame and blame on individuals by focusing on individuals’ responsibility for their weight); and (c) do not account for individual heterogeneity in body size and weight (i.e., generalize weight and health outcomes at the population level).”
In contrast we suggest that,
“Adopting a chronic disease framework for obesity would imply that both prevention and management strategies need to be implemented. Within this chronic disease context, public health should ensure that strategies do not have unintended consequences for individuals and populations, such as perpetuating weight bias. There is now sufficient evidence demonstrating that weight bias and obesity stigma are fundamental drivers of health inequalities. Public health has an opportunity to leverage existing health promotion frameworks such as the health for all policy framework and the global plan of action on social determinants of health to address weight bias and obesity stigma”.
Based on the analyses presented in this paper, we make the following recommendations:
Canadian provincial and territorial governments, employers, and the health insurance industry should officially adopt the position of the Canadian Medical Association and the World Health Organization that obesity is a chronic disease and orient their approach/resources accordingly.
Canadian provincial and territorial governments should recognize that weight bias and obesity stigma are significant barriers to helping people with obesity and enshrine rights in provincial/territorial human rights codes, workplace regulations, healthcare systems, and education policies.
In an era of people-centered health care, public health and health system decision makers should engage people with obesity in the development of policies and strategies. Having active participation of individuals with obesity can help change negative attitudes and beliefs about obesity and facilitate the development of compassionate and equitable health promotion strategies.
Employers should recognize and treat obesity as a chronic disease and provide coverage for evidence-based obesity treatments for their employees through health benefit plans.
Provincial and territorial governments should increase training for health professionals on obesity prevention and management.
Existing Canadian Clinical Practice Guidelines for the management and treatment of obesity in adults should be updated to reflect advances in obesity management and treatment in order to support the development of evidence-based programs and strategies by health systems, employers and health insurance companies.
In addition to the series of article on long-term outcomes in bariatric surgery, the 2018 special issue of JAMA on obesity, also features several articles discussing the potential role of taxing or otherwise regulating the use of sugar-sweetened beverages (SSB) as a policy measure to address obesity.
In a first article, Jennifer Pomeranz and colleagues discuss whether or not governments can in fact require health warnings on advertisements for sugar-sweetend beverages. The discussion focuses on an injunction issued by the Ninth Circuit Court on the enforcement of San Francisco’s requirement that sugar-sweetened beverage (SSB) advertisements display a health warning statement, finding that this law likely violated the First Amendment rights of advertisers of SSBs.
The background for this court decision was the fact that San Francisco passed a law requiring SSB advertisers to display: “WARNING: Drinking beverages with added sugar(s) contributes to obesity, diabetes, and tooth decay. This is a message from the City and County of San Francisco.”
In its decision, the court felt that the proposed warning label was not scientifically accurate, as it focussed exclusively on “added sugar(s)” rather than sugars overall. It appears that there is no scientific evidence suggesting that “added sugars” are any more (or less) harmful than the “natural” sugar occurring in any other foods or beverages).
However, as the authors argue, warning on SSB may well be warranted as
“In addition to being a major source of added sugar in the US diet, the liquid form of SSBs could enable rapid consumption and digestion without the same satiety cues as solid foods. SSBs also contain no relevant ingredients to provide offsetting health benefits, in comparison with sweetened whole grain cereals, nut bars, yogurt, or other foods with added sugars, which can have healthful components. Furthermore, the associations of SSBs with weight gain, obesity, type 2 diabetes, and heart disease are each stronger and more consistent than for added sugars in solid foods. In addition, compared with other foods containing added sugars, SSBs are the only source for which randomized controlled trials have confirmed the observational link to weight gain.”
Another point of contention identified by the court was related to the fact that the warning stated harm irrespective of quantity and would have been more accurate had it included the term “overconsumption” or at leas the qualifier “may”.
Here, the authors argue that,
“health risks of SSBs increase monotonically. Thus, use of the word “overconsumption” would not be scientifically accurate because there is no clear threshold effect between SSB consumption and harm. Yet, due to potential individual variation in responses, incorporating the word “may” or “can” would be scientifically accurate and are used in alcohol and smokeless tobacco warnings.”
The third objection by the court was related to the proposed size and rectangular border requirements of the warning, which was considered to be “unduly burdensome” – a point that the authors concede could be dealt with by modify formatting requirements by slightly reducing size, permitting “hairline” borders, or using other methods to ensure prominence and conspicuousness.
.In a second article on the issue of SSBs, Lisa Powell and Matthew Maciejewski discuss the case for taxing SSBs, noting they are the largest contributor of added sugar in the US diet, accounting for approximately 6.5% of total daily calories among adults and 7.3% among youth (ages 2-19 years) and approached 8% to 9% of daily calories among minority populations and 9% to 10% among low-income households. In addition consumption of SSBs have been associated with obesity as well as type 2 diabetes, cardiovascular disease, dental caries, and osteoporosis.
As the authors point out, for SSB taxes to be effective, the increased cost of SSBs has to be passed on to the consumer (“pass-through) and the consumer has to respond by decreasing their consumption (“price elasticity”). In places where SSB taxes have been implemented (e.g. Mexico), both effects have been seen, suggesting that an SSB tax can indeed change consumer behaviours.
However, as the authors also note, so far there is little evidence directly demonstrating that such changes have translated into actual health outcomes (for obesity or otherwise).
Nevertheless, the authors feel that an SSB tax can effectively decrease the overall consumption of these beverages and should perhaps be extended even further to include all forms of sugary drinks including 100% fruit juice. For this approach to be broadly acceptable, it would also be important to dedicate any revenue from these taxes to specific educational or public health purposes.
Finally, a third article on this issue by John Cawley deals with an interesting “quasi experimental” pass-through effect of SSB taxes at the Philadelphia International Airport, which happens to straddle the city border, with some terminals in Philadelphia that are subject to the beverage tax (1.5 cents per ounce), and other terminals in Tinicum that are not.
The study included 31 stores: 21 on the taxed side of the airport (Philadelphia) and 10 on the untaxed side (Tinicum).
As the authors found, following the implementation of the SSB tax in Philadelphia, the average price of SSBs increased on both the taxed and untaxed side of the airport (albeit more so on the taxed side). Using only data for taxed stores, the percentage of the tax passed on to consumers was 93%. Overall, however, the price difference between the taxed and untaxed stores was about 0.83 cents per ounce (a 55% relative pass-through rate).
Thus, while the tax did have a significant effect on SSB pricing in Philadelphia, it appears that the non-taxed stores simply went along to increase their profit margins accordingly.
Whether or not these changes in pricing had any impact on actual SSB sales or consumption was not reported.
Together, these studies certainly support the statement by Powell and Maciejewski that
“SSB taxes are likely to remain controversial for some time and policy makers will have a number of issues to consider as they formulate and implement fiscal policies.”
“SSB taxation can only be one approach to what must be a multipronged public health strategy to reduce obesity via improved diets and increased activity. The fact that intake of SSBs has declined over the past decade and the obesity epidemic has continued unabated suggests that reducing SSBs alone is not the sole solution. Adults and youth who frequently consume SSBs are more likely to engage in other unhealthy behaviors (eg, inactivity, greater fast-food consumption), so population-based policies specifically targeting these behaviors need to be designed in concert with SSB taxes. Although SSB consumption remains high in the United States, particularly among vulnerable populations, and taxation is a viable tool for curbing its consumption, the long-run intended and unintended effects of SSB tax policy are yet to be determined. The debate on its merits as an effective tool to improve health outcomes will be greatly informed by rigorous evidence on consumption, sugar intake, and body weight both on average and within vulnerable populations (children, minorities, low-income individuals).”
This week, JAMA revisits obesity with a dedicated theme issue, which includes a range of articles on obesity prevention and management (including several on the impact of taxing sugar-sweetened beverages and five original long-term studies on bariatric surgery).
In an accompanying editorial, Edward Livingston notes that,
“The approach to the prevention and treatment of obesity needs to be reimagined. The relentless increase in the rate of obesity suggests that the strategies used to date for prevention are simply not working.”
“From a population perspective, the increase in obesity over the past 4 decades has coincided with reductions in home cooking, greater reliance on preparing meals from packaged foods, the rise of fast foods and eating in restaurants, and a reduction in physical activity. There are excess calories in almost everything people eat in the modern era. Because of this, selecting one particular food type, like SSBs, for targeted reductions is not likely to influence obesity at the population level. Rather, there is a need to consider the entire food supply and gradually encourage people to be more aware of how many calories they ingest from all sources and encourage them to select foods resulting in fewer calories eaten on a daily basis. Perhaps tax policy could be used to encourage these behaviors, with taxes based on the calorie content of foods. Revenue generated from these taxes could be used to subsidize healthy foods to make them more affordable.”
Over the next few days, I will be reviewing about the individual articles and viewpoints included in this special issue.
In the meantime, the entire issue is available here.