To conclude this brief series on our new exhaustive review of the putative health benefits of long-term weight-loss maintenance, published in Annual Reviews of Nutrition, here is the summary paragraph of our findings:
“Obesity is well recognized as a risk factor for a wide range of health issues affecting virtually every organ system. There is now considerable evidence that intentional weight loss is associated with clinically relevant benefits for the majority of these health issues. However, the degree of weight loss that must be achieved and sustained to reap these benefits varies widely between comorbidities. Downsides of weight loss that is too rapid and/or extreme may occur, as in the increased risk of gallbladder disease, the presence of excess residual skin, or deterioration in liver histology. Uncertainty also remains about the potential benefit or harm of intentional weight loss on patients presenting with some chronic diseases and on overall mortality. Clearly, well- controlled prospective studies are needed to better understand the natural history of obesity and the impact of weight-management interventions on morbidity, quality of life, and mortality in people living with obesity.”
The is much left to be done and answering some of these questions will become progressively easier as better treatments for obesity become available.
In our exhaustive review of the potential health benefits of intentional long-term weight loss, published in Annual Reviews in Nutrition, I discussed in yesterday’s post, we also noted a number of issues that remain unresolved.
- The precise definition of success in terms of weight loss remains controversial, and the dogmatic assumption that prolonged periods of sustained weight loss (greater than 10 years) are more likely than shorter periods to have a beneficial effect on health out- comes has never been challenged.
- Some evidence suggests that intentional weight loss may lead to meaningful reductions in several conditions, such as COPD, and cancer risk with a short latency time, although data from randomized trials are not yet available to support this hypothesis.
- Future studies on the relationship between long-term weight loss and suicide are needed, especially in diverse populations, subgroups of patients, and those who engage in other long-term weight-loss strategies apart from the use of antiobesity medications and bariatric surgery. The potential relationship between failed weight-loss attempts and suicide ideation needs to be evaluated.
- There is ongoing controversy over the findings from epidemiological studies on the relationship between weight loss and mortality. Data from controlled studies in this regard are very limited.
Clearly, as we discussed at length here at the ongoing Canadian Obesity Network’s Obesity Research Summer School (Boot camp), much remains to be done for young researchers planning a career in this field.
Hard to believe, but this weekend I am off to my 10th annual Canadian Obesity Network Summer Boot Camp – once again in Kananaskis in the Canadian Rockies.
As every year, I look forward to spending 9 days with an enthusiastic bunch of young obesity researchers and professionals as well as my faculty colleagues, who will teach about everything from genetics and molecular biology to public health and clinical management.
More importantly, the intense networking involved in this event, as in the past, should lead to a lasting network of professional friendship across disciplines, research interests and countries.
I am certain that the almost 300 alumni of this camp can attest to how much this experience has influenced their thinking and professional development.
Thanks to all at the Canadian Obesity Network, who make this annual event possible.
According to a study conducted by a team of researchers from the US, Canada, Australia and Iceland, published in Pediatric Obesity, weight-based bullying in children and youth is the most prevalent form of youth bullying in these countries, exceeding by a substantial margin other forms of bullying including race/ethnicity, sexual orientation or religion.
According to the almost 3000 participants in this study, parents, teachers and health professionals were seen as those with the greatest potential of reducing weight-based bullying.
In addition, the majority of participants (65-87%) supported government augmentation of anti-bullying laws to include prohibiting weight-based bullying.
While these findings may not strike anyone living with obesity as surprising, they should be a reminder to the rest of us that weight-based bullying, with all of its negative consequences for mental, physical and social health, is something to be taken very seriously and needs to be opposed as much as we would oppose any other forms of bullying.
If anyone ever tells you that the current obesity epidemic can have nothing to do with genetics because “genes don’t change in a couple of generations”, it is completely fair to let them know that they probably do not know what they are talking about.
Indeed, there is now overwhelming evidence showing that a variety of health problems, particularly related to metabolic diseases including obesity, can well be transmitted from generation to generation as a result of epigenetic modifications that persist in subsequent generations, even if these are no longer exposed to the “trigger” environment.
Anyone who is interested in learning about how much we know about these intergenerational mechanisms, will probably want to read a recent review article on this subject by Rachel Stegemann and David Buchner, published in Seminars in Cell & Developmental Biology.
In this papers the authors review examples of transgenerational inheritance of metabolic disease in both humans and model organisms and how these can be triggered by both genetic and environmental stimuli.ors
As the authors note,
“A diverse assortment of initial triggers can induce transgenerational inheritance including high-fat or high-sugar diets, low-protein diets, various toxins, and ancestral genetic variants. Although the mechanistic basis underlying the transgenerational inheritance of disease risk remains largely unknown, putative molecules mediating transmission include small RNAs, histone modifications, and DNA methylation.”
They also discuss example of therapeutically targeting the epigenome (e.g. through dietary modification or exercise) to prevent the transgenerational transmission of metabolic disease.
These findings have substantial implications for our attempts to prevent or even reverse the development of obesity in future generations.