Etiological Assessment of Obesity: Factors Affecting Ingestive Behaviour
Continuing with citations from my article in Obesity Reviews on an aeteological framework for assessing obesity, we now turn to the some of the factors that can affect ingestive behaviour. Once you have quickly established that weight gain is not primarily driven by a change (decrease) in metabolic requirements, you turn to the most likely cause of weight gain – eating more calories than your body actually needs: Ingestive behaviour, which includes both eating and drinking, accounts for 100% of total energy intake. In contrast to total energy expenditure, caloric intake (on a daily basis) can vary from zero (fasting) to several times that of total energy requirements (e.g. during a binge eating episode). Given the ease with which it is possible for energy intake to exceed caloric expenditure, it is therefore not surprising that caloric hyperalimentation is a major determinant of weight gain. Any assessment of obesity or increase in body weight thus requires a careful assessment of ingestive behaviour. Evidence for caloric hyperalimentation or hyperphagia should in turn prompt systematic exploration of the determinants of this behaviour. In this context, it helps to view over‐eating as a symptom of an underlying perturbation of ingestive behaviour rather than simply a wilful behavioural choice. While the socio‐psycho‐neurobiological determinants of ingestive behaviour are exceedingly complex, in clinical practice, it is possible to divide them into four domains: socio‐cultural factors, biomedical or physiological (homeostatic) factors, psychological (hedonic) factors and medications. In a given individual, these domains are intimately connected and show considerable variation and overlap. Nevertheless, in practice it is often possible to determine the primary domain that explains the excess caloric intake in a given individual and can thus provide the key to developing a treatment plan that addresses the root cause of this behaviour. More on the various factors affecting ingestive behaviour in coming posts. @DrSharma Edmonton, AB
There Is More To Obesity Than Just Energy In and Energy Out
Continuing with citations from my article in Obesity Reviews on an aeteological framework for assess obesity, I have the following quote to offer: In the same manner in which a complete understanding of oedema requires the assessment of the complex physiological systems affecting fluid and sodium homeostasis, understanding obesity requires a comprehensive appreciation of the multitude of factors affecting energy intake and expenditure. Energy expenditure can be further subdivided into non‐activity (= resting metabolic rate + dietary‐induced thermogenesis) and activity thermogenesis (= non‐exercise + exercise activity thermogenesis). For simplicity’s sake, these three elements can be termed diet, metabolism and activity. A change in any one of these elements, if not balanced by corrective changes in the others, will result in a net change in energy balance, which, if positive, will result in caloric ‘retention’ and weight gain. In subsequent posts, I will discuss the many factors that can affect energy metabolism, food intake, and physical activity and how changes to each (if not balance by corrective changes in the others) can lead to weight gain and often pose barriers to obesity management. Stay tuned…. @DrSharma Edmonton, AB
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 »
Counting Calories For Weight Loss – More of The Same
If there is one article in the 2018 special issue of JAMA on obesity that we could have well done without, it is surely the one by Eve Guth promoting the age-old notion that simply counting calories is a viable and effective means to manage body weight. As the author suggests: “It is better for physicians to advise patients to assess and then modify their current eating habits and then reduce their caloric ingestion by counting calories. Counseling patients to do this involves provision of simple handouts detailing the calorie content of common foods, suggested meal plan options, an explanation of a nutrition label, and a list of websites with more detailed information. Patients should be advised that eating about 3500 calories a week in excess of the amount of calories expended results in gaining 1 lb (0.45 kg) of body weight. If a patient reduces caloric ingestion by 500 calories per day for 7 days, she or he would lose about 1 lb of body weight per week, depending on a number of other factors. This is a reasonable and realistic place to start because this approach is easily understood and does not ask a patient to radically change behavior.” There is so much wrong with this approach, that it is hard to know exactly where to start. For one, this advise is based on the simplistic assumption that obesity is simply a matter of managing calories to achieve and sustain long-term weight loss. Not only, do we have ample evidence that these type of approaches rarely result in long-term sustained weight-loss but, more importantly this type of advice comfortably ignores the vast body of scientific literature that tells us that body weight is a tightly regulated physiological variable and that there are a host of complex neuroendocrine responses that will defend our bodies against long-term weight loss – mechanisms that most people (irrespective of whether they have obesity or not) will find it exceedingly hard to overcome with “will-power” alone. No doubt, caloric “awareness” can be an eye-opener for many patients and there is good evidence that keeping a food journal can positively influence dietary patterns and even reduce “emotional” eating. But the idea that cognitively harnessing “will-power” to count calories (a very “unnatural” behaviour indeed), thereby creating and sustaining a long-term state of caloric deficit is rather optimistic at best. In fact, legions of people who have been… Read More »
Taxing Sugar-Sweetened Beverages To Prevent Obesity
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… Read More »
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