Obesity Can Be Conceptualized As “Caloric Retention”
Several years ago, my colleague Raj Padwal and I published a paper in Obesity Reviews, where we outline a rational approach to an aetiological assessment of obesity. As many readers may not have seen this paper, I will repost several of the key elements we discussed in it. Although some of our thinking has evolved since then, I believe the overall reasoning remain as relevant today, as when we first wrote the paper back in 2010: Obesity is characterized by the accumulation of excess body fat and can be conceptualized as the physical manifestation of chronic energy excess. Using the analogy of oedema, which is the consequence of positive fluid balance or fluid retention, obesity can be seen as the consequence of positive energy balance or caloric retention. Just as the positive fluid balance of oedema can result from a host of underlying aetiologies including cardiac, hepatic, renal, endocrine, infectious, venous, lymphatic or drug‐related causes, obesity can result from a wide range of aetiologies that promote positive energy balance. As with oedema, assessment and management of obesity requires an exploration of the root causes and underlying pathologies. To extend the obesity–oedema analogy, addressing all forms of obesity simply with caloric restriction and exercise (‘eat less and move more’) would be akin to addressing all forms of oedema simply with fluid restriction and diuretics. As this narrowly focused approach is not considered standard‐of‐care in managing patients with oedema, why should it be considered as the preferred method of treating obesity? The classical treatment of obesity, based on increased physical activity and decreased calorie intake, has not been successful. Approximately two‐thirds of the people who lose weight will regain it within 1 year, and almost all of them within 5 years. In our opinion, the lack of efficiency in these therapeutic approaches is likely due to an incomplete understanding of the precise aetiology or aetiologies of obesity and, consequently a failure to address the root causes of energy imbalance. In this paper, we present a theoretical diagnostic paradigm that provides an aetiological framework for the systematic assessment of obesity and discuss how this framework can enhance our ability to diagnose and manage obesity in clinical practice. The framework considers socio‐cultural, physiological, biomedical, psychological and iatrogenic factors that can determine energy input, metabolism and expenditure. Comment: In hindsight, I would note that apart from failure to address the underlying pathology and drivers of… Read More »
Liraglutide Effects on Upper Gastrointestinal Investigations: Implications Prior to Bariatric Surgery
With the considerable waits that patients in Canada often face prior to bariatric surgery, we generally recommend that patients, who have access to them, try anti-obesity medications while waiting. This not only prevents further wait gain, but also often helps them shed a significant amount of weight prior to surgery. The GLP-1 analogue liraglutide is now approved for long-term obesity treatment and is generally well tolerated. Nevertheless, we now present a series of patients in Obesity Surgery, who were treated with liraglutide 3.0 mg whilst waiting for bariatric surgery, and showed significant upper GI dismotility that was reversible on discontinuation of liraglutide. Although, investigations of upper GI motility are by no means part of routine assessment for bariatric surgery, tests may be ordered in patients who present with unclear upper GI symptoms, as the findings may guide the choice of surgical intervention. In this paper, we present six cases in which patients treated with liraglutie 3.0 mg presented with varying degrees of esophageal and/or gastric dysmotility demonstrated using a variety of investigative procedures including formal gastric emptying scintiography as well as less specific esophageal manometry, and upper endoscopy. In all cases normal motility was restored on discontinuation of liraglutide and all patients subsequently underwent or are continuing to wait for bariatric surgery. Based on our observations we discuss that, “Liraglutide is associated with decreased esophageal peristalsis and gastric emptying. These effects can result in abnormal upper GI investigations, leading to delays, increased testing, and questions of patient candidacy for surgery. If patients on liraglutide are noted to have abnormal esophageal manometry or gastric emptying studies, medication should be discontinued, with repeat studies done to look for reversibility. If this abnormal result is due to drug effect, this should not preclude patients from having bariatric surgery.” Just how long liraglutide needs to be stopped prior to performing upper GI investigations remains unclear. Furthermore, as the dysmotility often appears to be symptomless and well-tolerated, we do not recommend routine ordering of motility tests in patients treated with liraglutide. @DrSharms Edmonton, AB Disclaimer: I have served as a consultant and speaker for Novo Nordisk, the makers of liraglutide.
When To Recommend Weight Loss For Obesity
Obesity medicine, which I define as the medical care of someone living with obesity, should approach patients holistically with the aim of improving their overall health and well-being. Advice to lose weight may or may not be part of obesity management – much can be gained for someone living with obesity by promoting their health behaviours, getting them to feel better about themselves, improving their mental health, and helping them better managing their health issues. Much of this can be achieved with no or very little weight loss. Thus, we must consider the question of when weight loss would specifically need to be part of the treatment objectives. In my own practice, I approach this problem by considering the following three questions: Is this a problem unrelated to abnormal or excess body weight? Is this a problem aggravated by abnormal or excess body weight? Is this a problem caused by abnormal or excess body weight? From what I hear from my patients, the most common mistakes in medical practice fall into the first group – trying to address unrelated issues with weight loss recommendations. There are endless stories of patients going to see their health provider with problems clearly unrelated to their body fat (e.g. a broken arm, a sore throat, the flu, depression, migraines, etc.), who simply get told to lose weight. Indeed, there is evidence to suggest that patients with obesity are less likely to undergo diagnostic testing, most likely based on the assumption that their problems are simply related to their excess weight. This is not only where grave medical errors can be made (late or misdiagnosis), but also where the advice to lose weight is clearly wrong. If the presenting problem has nothing to do with excess weight, then no amount of weight loss will fix it. The second category deals with issues that are not causally related to abnormal or excess body fat but where the underlying problem either causes more symptoms or is more difficult to treat because of the patient’s size or fat distribution. There are countless medical problems that fall into this category. For e.g. a heart or respiratory problem entirely unrelated to excess weight (e.g. a valvular defect or asthma) can become worse, cause more symptoms, or be much more difficult to treat simply because of the patient’s size. This group also includes issues like neck or joint pain from a trauma… Read More »
The Heterogeneity of Obesity
In the same manner in that there is not one predisposing factor for the development of obesity, the phenotypic clinical presentation of obesity is likewise extraordinarily heterogenous. (This has some authors speaking of “obesities” rather than “obesity”). While it is now well established that BMI is a measure of size rather than health, it is perhaps less well recognised how the different types of body fat and their storage in various fat depots and organs can contribute to cardiometabolic disease (location, location, location!). Now, a comprehensive review by Ian Neeland from the University of Texas Southwestern Medical Center, Dallas, together with my colleagues Paul Poirier and JP Despres from Laval University in Quebec, published in Circulation discusses the cardiovascular and metabolic heterogeneity of obesity. As the authors point out, “Although the BMI has been a convenient and simple index to monitor the growth in obesity prevalence at the population level, many metabolic and clinical studies have revealed that obesity, when defined on the basis of the BMI alone, is a remarkably heterogeneous condition. For instance, patients with similar body weight or BMI values have been shown to display markedly different comorbidities and levels of health risk.” Not only has BMI never emerged as a significant component in risk engines such as the Framingham risk score, there are many individuals with obesity who never develop metabolic complications or heart disease during the course of their life. The paper offers a good review of what the author describe as adipose dysfunction or “adiposopathy” = “sick fat”. Thus, in some individuals, there is an accumulation of “unhealthy” fat (particularly visceral and ectopic fat), whereas in others, excess fat predominantly consists of “healthy” fat (predominantly in subcutaneous depots such as the hips and thighs). The authors thus emphasise the importance of measuring fat location with methods ranging from simple anthropometric measures (e.g. waist circumference) to comprehensive imaging techniques (e.g. MRI). The authors also provide a succinct overview of exactly how this “sick fat” contributes to cardiometabolic risk and briefly touches on the behavioural, medical, and surgical management of patients with obesity and elevated cardiometabolic risk. I, for one, was also happy to see the inclusion of the Edmonton Obesity Staging System in their reflections on this complex issue. This paper is certainly suggested reading for anyone interested in the link between obesity and cardiovascular disease. @DrSharma Edmonton, AB
How Precise Can Obesity Medicine Get?
Another article in the 2018 JAMA special issue on obesity is one by Susan and Jack Yanovski and deals with the issue of using a precision or “personalised” approach to obesity prevention and management. As we know, there are myriad factors that can lead to obesity (environmental, genetic, psychological, medical, etc., etc., etc.), with each patient having their own story and set of drivers and barriers. Furthermore, we know that for any given treatment (whether behavioural, medical, or surgical) there is wide variation in individual outcomes. So, being able to match the right treatment to the right patient, or even better, reliably predict a given patient’s response to a specific treatment could potentially improve outcomes and reduce patient burden and costs. However, as the authors note, currently the only real predictor to treatment response is how well patients respond during the early part of treatment. Thus, we know that patient who lose a significant amount of weight during the first few weeks of medical treatment, tend to have the best long-term success in terms of weight loss. However, this approach is also rather limited. In my own practice, I regularly see patients, who initially do well with behavioural, medical or surgical treatments, but eventually struggle, as well as patients who take longer to respond to a treatment before ultimately doing fine in the long term. We are of course a long way off from having any kind of genetic or other testing that would reliably predict patient responses to treatment. While this may become possible in the future, I am not holding my breath. Not only is every patient’s story different, but the many factors that can determine response (societal, behavioural, psychological, biological, etc.) are almost endless and, moreover, can even vary over time in a given individual. In fact, for most complex chronic diseases (e.g. diabetes, hypertension, depression, etc.), finding the best treatment for a given patient continues to be “trial and error”, or in other words, “empirical”. Despite all the progress in genetic research, this has not really changed for most other complex chronic diseases like hypertension, type 2 diabetes, or dyslipidemia (despite a few rare but notable exceptions). Moveover, as the authors point out, there are many other factors that will determine whether or not a given patient even has access to certain treatments, irrespective of whether or not that treatment is indeed the best treatment for… Read More »
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