While the health benefits associated with intentional weight loss for some complications of obesity (such as elevated lipids and diabetes) are well documented, high-quality studies to back many other potential health benefits are harder to find.
Just how well (or poorly) the putative health benefits of long-term intentional weight loss are documented for each of the many conditions associated with obesity, is now detailed in a comprehensive review of the literature that we just published in the Annual Reviews of Nutrition.
The 40 page long review, which includes almost 250 relevant publications, supports the following main findings:
- Defining and assessing clinically relevant obesity and weight change are challenging tasks. In a given individual, there is often little relationship between the magnitude of obesity and measures of health.
- Despite its modest effect on long-term weight loss, behavioral modifications thatimprove eating behaviors and increase physical activity constitute a cornerstone for integral and sustainable weight management.
- Intentional weight loss is associated with a clinically relevant reduction in blood pressure, improvement in cardiac function, and reduction in cardiovascular events. The duration and magnitude of weight change required to achieve a significant benefit are still unclear.
- In individuals with impaired glucose metabolism at any stage, intentional weight loss achieved by any means is associated with a proportional reduction in T2DM prevalence, severity, and progression.
- Intentional weight loss is consistently associated with a clinically relevant reduction in triglycerides and increase in HDL cholesterol. The effects of weight loss on LDL cholesterol are less consistent.
- Overall, nonalcoholic fatty liver disease is commonly associated with excess weight and can show marked improvement with behavioral, pharmacological, and/or surgical weight loss. Very rapid weight loss, however, may worsen liver histology in some patients. Simi- larly, gallbladder disease is not only common in patients presenting with obesity but also highly prevalent after intentional weight loss.
- Obesity is widely recognized as a key modifiable risk factor for osteoarthritis, with sig- nificant improvements in pain and function reported with weight loss.
- Obstructive sleep apnea and obesity hypoventilation syndrome tend to improve with moderate weight loss; however, complete resolution is not common and is related to very significant weight loss.
- Asthma and COPD are clearly associated with obesity. Sustained weight loss seems to be associated with a significant improvement in asthma symptoms. Data for COPD are rather limited.
- Pregnant women who under go bariatric surgery seem to be less likely to present obstetric complications such as gestational diabetes, preeclampsia, and macrosomia.
- Data on weight loss and suicide are controversial. Caution may be in order when con- sidering bariatric surgery in patients with a history of suicide ideation or attempt.
- Data suggest that long-term weight loss is associated with an improvement in health- related quality of life. The amount of weight loss required to achieve a significant change, however, remains controversial.
However, there are many other issues where putative benefits of intentional weight loss remain even less clear than with the above.
For many conditions we will likely not know the long-term benefits of obesity treatments till better treatments become available and are tested in affected individuals.
As a clinician often dealing with patients presenting with binge-eating disorder (BED), I am quite aware of the often pathological cognitive and emotional relationship to food, eating, and body image presented by patients with this syndrome.
Whether or not this impairment in thinking and feeling also extends to other behavioural or emotional domains is the topic of a systematic review by Kittel and colleagues from the University of Leipzig, published in the International Journal of Eating Disorders.
The paper is based on the review of almost 60 studies and shows that, individuals with BED consistently demonstrate higher information processing biases compared to obese and normal-weight controls in the context of disorder-related stimuli (i.e., food and body cues) – in contrast, cognitive functioning in the context of neutral stimuli appear to be less affected.
With regard to emotional functioning, individuals with BED also report greater emotional deficits when compared to obese and normal-weight controls.
Thus, these findings confirm the clinical observation that patients with BED tend to have specific difficulties in cognitive and emotional functioning when it comes to food, eating or body image, however, appear to function adequately in other domains.
For clinicians these finding are relevant as they show that while people with BED may benefit from help in changing their cognitive and emotional response to food cues, such problems are indeed more often encountered in people with BED rather than in everyone living with obesity.
Screening for BED should be an essential element of workup in anyone presenting with excess weight gain.
Irrespective of the fact that bariatric surgery has now become so safe (at high-volume centres) that it compares well with other common surgical procedures like having your gall bladder removed, it is still surgery.
As even the safest surgery carries risk, it should never be taken lightly and thus the question of whether or not people with obesity but no related comorbidities stand to benefit from bariatric surgery is an important question.
One of the key outcomes (at least for patients) is the impact on quality of life which is why Hilde Risstad and colleagues from the University of Oslo, studied the effect of bariatric surgery on patients presenting with obesity related comorbidities and those without, published in Obesity Surgery.
They studied 232 patients with severe obesity before and 2 years after Roux-en-Y gastric bypass.
Obesity related disease was defined as having at least one of the following conditions: type 2 diabetes mellitus, hypertension, dyslipidemia, coronary heart disease, obstructive sleep apnea, gastroesophageal reflux disease, or osteoarthritis.
Not only was baseline quality of life similar in patients with and without obesity-related disease prior to gastric bypass but it also improved equally in both groups.
This may not be entirely surprising.
Readers may recall that the Edmonton Obesity Staging System (EOSS), specifically designed to asses obesity related health risks, does not just consider medical comorbidities (as in this study) – EOSS gives as much importance to mental and functional health (not assessed in this study).
Thus, it is not surprising, that even without the presence of an obesity related medical complications like diabetes or sleep apnea, health (and thus quality of life) can be significantly affected by mental health and/or functional status, both of which can markedly improve after bariatric surgery.
This is why, pre-assessment or triaging patients for bariatric surgery should not only consider medical problems but also mental and functional health – as in EOSS.
Regular readers will be well of the very real social and health impact of weight bias and discrimination.
Now, Sara Kirk of Dalhousie University, Halifax, NS, invites you to join her free Massive Open Online Course (MOOC), on weight bias and stigma in obesity, which will be starting on April 20th 2015 (just a week before the Canadian Obesity Summit in Toronto).
The course builds on Kirk’s extensive research in this area and the dramatic presentation that was created from her findings.
Participants will be able to explore some of the personal and professional biases that surround weight management and that impact patient care and experience.
This will hopefully give health professionals better insight into how to approach individuals experiencing obesity in a respectful and non-judgmental manner and provide strategies to build positive and supportive relationships between health care providers and patients.
While targeted at health care providers, the course should also be of interest to anyone interested in learning more about what weight bias is and how it can impact health and relationships.
Participants who complete the course requirements can apply for a citation of completion (for a nominal fee).
Following the recent release of the Canadian Task Force on Preventive Health Care guidelines for prevention and management of adult obesity in primary care, the Task Force yesterday issued guidelines on the prevention and management of childhood obesity in the Canadian Medical Association Journal (CMAJ).
Key recommendations include:
- For children and youth of all ages the Task Force recommends growth monitoring at appropriate primary care visits using the World Health Organization Growth Charts for Canada.
- For children and youth who are overweight or obese, the Task Force recommends that primary health care practitioners offer or refer to formal, structured behavioural interventions aimed at weight loss.
- For children who are overweight or obese, the Task Force recommends that primary health care practitioners not routinely offer Orlistat or refer to surgical interventions aimed at weight loss.
The lack of enthusiasm for the prevention of childhood obesity is perhaps understandable as the authors note that,
“The quality of evidence for obesity prevention in primary care settings is weak, with interventions showing only modest benefits to BMI in studies of mixed-weight populations, with no evidence of long-term effectiveness.”
leading the Task Force to the following statement,
“We recommend that primary care practitioners not routinely offer structured interventions aimed at preventing overweight and obesity in healthy-weight children and youth aged 17 years and younger. (Weak recommendation; very low-quality evidence)”
Be that as it may, the Task Force does recommend structured behavioural interventions for kids who already carry excess weight based on the finding that,
“Behavioural interventions have shown short-term effectiveness in reducing BMI in overweight or obese children and youth, and are the preferred option, because the benefit-to-harm ratio appears more favourable than for pharmacologic interventions.”
What caught my eye however, was the statement in the accompanying press release which says that,
“Unlike pharmacological treatments that can have adverse effects, such as gastrointestinal problems, behavioural interventions carry no identifiable risks.” (emphasis mine)
While I would certainly not argue for the routine use of orlistat (the only currently available prescription drug for obesity in Canada) in children (or anyone else), I do take exception to the notion that behavioural interventions carry no identifiable risks – they very much do.
As readers may be well aware, a large proportion of the adverse effects of medications is attributable to the wrong use of these medications – problems often occur when they are taken for the wrong indication, at the wrong dose (too high or too low), the wrong frequency (too often or too seldom), and/or when patients are not regularly monitored. In a perfect world, many medications that often lead to problems would be far less problematic than they are in the real world.
Interestingly, the same applies to behavioural interventions.
Take for example diets – simply asking a patient to “eat less” can potentially lead to all kinds of health problems from patients drastically reducing protein, vitamin and mineral intake as a result of going on the next “fad” or “do-it-yourself” diet. Without ensuring that the patient actually follows a prudent diet and does not “overdo” it, which may well require ongoing monitoring, there is very real potential of patients harming themselves. There is also the real danger of promoting an eating disorder or having patients face the negative psychological consequences of yet another “failed” weight-loss diet. Exactly how many patients are harmed by well-meant dietary recommendations is unknown, as I am not aware of any studies that have actually looked at this.
The same can be said for exercise – simply asking a patient to “move more” can result in injury (both short and long-term) and coronary events (in high-risk patients). Again, ongoing guidance and monitoring can do much to reduce this potential harm.
In short when patient apply behavioural recommendations at the wrong dose (too much or too less), wrong frequency (too often or too seldom), and/or are not regularly monitored, there is indeed potential for harm – I would imagine that this potential for harm is of particular concern in kids.
This is not to say that we should not use behavioural interventions – we should – but we must always consider the potential for harm, which is never zero.
I’d certainly be interested in hearing from anyone who has seen harm resulting from a behavioural intervention.