Factors Affecting Ingestive Behaviour: Physiological or Homeostatic Factors
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: Physiological or Homeostatic Factors In contrast to excess caloric consumption that results largely from environmental determinants, over‐eating in response to increased hunger or reduced satiety can be viewed as a physiological response to a perturbation of the homeostatic system and is perhaps best termed homeostatic hyperphagia. Primary homeostatic hyperphagia can result from genetic defects in the homeostatic system (e.g. leptin deficiency, melanocortin type 4 receptor mutation or Prader Willi Syndrome) and are rare. Secondary homeostatic hyperphagia can result from acquired defects or perturbations in the homeostatic system (e.g. head trauma, craniopharyngeoma, insulinoma). Tertiary homeostatic hyperphagia, by far the most common category, is largely the result of inappropriate feeding intervals and/or nutrient selection. Thus, skipping meals, resulting in a compensatory hyperphagic response (rapid ingestion of energy‐dense foods), is perhaps the most prevalent form of homeostatic hyperphagia. Ingestion of high‐glycemic foods resulting in a rapid rise and fall in blood glucose and insulin levels (‘crash and crave’) may prompt increased snacking and overconsumption, although this notion remains controversial. Meal duration and composition can also affect satiety response, whereby delayed or reduced satiation (e.g. in response to hasty eating, energy‐dense foods, low fibre intake, liquid calories) can result in excess caloric intake. The presence of homeostatic hyperphagia (characterized by over‐eating in response to increased hunger and/or reduced satiety) will likely call for interventions that specifically address the underlying perturbation in this system (e.g. administration of leptin, excision of the insulinoma, correction of meal pattern, nutritional hygiene, portion control, etc.). Patients with obesity resulting from tertiary homeostatic hyperphagia are the most likely to benefit from dietary counselling. @DrSharma Edmonton, AB
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
Why Weight-Loss Challenges Send the Wrong Message
I was recently, once again asked about my opinion on weight-loss challenges. So here is a repost of an article I wrote back in 2008 on this topic – apparently, it is still as relevant today, as it was almost a decade ago. There appears to be a rather widespread notion out there that introducing a bit of competition into the affair may spurn people on to try and lose those “extra” pounds. In fact, a quick google search on the term “weight-loss challenge” reveals an amazing array of challenges from voyeuristic and sadistic TV shows like the “Biggest Loser” to well-meant workplace wellness initiatives or fund raisers. I am sorry to admit that I recently even became aware of a weight-loss challenge within my own hospital – well intended, but useless in the fight against obesity. So what’s wrong with this idea? Isn’t competition a great motivator? Sure it is – and people will do anything to win a competition – including crazy stuff like starve themselves, exercise till they drop, or even (God forbid) pop diet pills, diuretics or laxatives just to win. All of this is in direct contradiction to a fundamental principle of obesity management: you do not do things to lose weight that you are unlikely to continue doing to keep the weight off. Most people seem to think that if only they could lose some weight, they will somehow be able maintain that lower body weight in the long-term with less effort. The reality unfortunately is (and most dieters have experienced this over and over again) that no matter what diet or exercise routine you chose, no matter how slow or fast you lose the weight, no matter how long you keep the weight off – the minute you relax your efforts, the weight simply comes back. As I have blogged before: obesity is a chronic disease for which we have no cure – only treatments! When you stop the treatment the weight (and any related problem) simply comes back. By now you will already have figured out the problem with these challenges – unless you are very modest and reasonable about your weight-loss target and are carefully making changes that you can reasonably sustain forever, you are simply setting yourself up for failure. If you are indeed modest and reasonable – you’ve already lost the competition to all the crazy folks who’ll do… Read More »
New European Guidelines on Medical Management After Bariatric Surgery
The European Association for the Study of Obesity (EASO) had now released the new OMTF guidelines Practical Recommendations of the Obesity Management Task Force of the European Association for the Study of Obesity for Post-Bariatric Surgery Medical Management. The guidelines provide the latest guidance on nutritional management, micronutrient supplementation, managing co-morbidities, pharmacotherapy, psychological management, and prevention and management of weight regain. The guidelines also address the issue of post-bariatric surgery pregnancy. Not covered are issues related to dealing with excess skin and rehabilitation (e.g. return to work, reintegration in social activities, education, etc.), both of significant importance, especially in people with severe obesity. As the authors note, “Bariatric surgery is in general safe and effective, but it can cause new clinical problems and it is associated with specific diagnostic, preventive and therapeutic needs. Special knowledge and skills of the clinicians are required in order to deliver appropriate and effective care to the post-bariatric patient. A post-bariatric multidisciplinary follow-up programme should be an integral part of the clinical pathway at centres delivering bariatric surgery, and it should be offered to patients requiring it” These guidelines are now available open access in Obesity Facts. @DrSharma Edmonton, AB
Conflict Disclosures In Nutrition Research
As someone who has often engaged in research projects, consultation, or speaking engagements sponsored or otherwise supported by industry (all of which I happily acknowledge and declare), I am a keen observer of the ongoing discussion about when and how researchers need to be wary of potential biases and conflicts. As I pointed out in previous posts, among all of the potential conflicts, the financial one is perhaps the easiest to declare and otherwise manage. A recent article by John Ionnadis and John Trepanowski, published in JAMA, discusses the wide range of conflicts (most of which may be non-financial), that one may wish to have declared and exposed, especially when it comes to nutrition research. The authors single our nutrition research for good reasons: “…the totality of an individual’s diet has important effects on health, most nutrients and foods individually have ambiguously tiny (or nonexistent) effects. Substantial reliance on observational data for which causal inference is notoriously difficult also limits the clarifying ability of nutrition science. When the data are not clear, opinions and conflicts of interest both financial and nonfinancial may influence research articles, editorials, guidelines, and laws. Therefore, disclosure policies are an important safeguard to help identify potential bias. “ While the potential for financial conflict in relationship to the food industry is well recognised and there are now well-established “disclosure norms”, other conflicts, of which there are many, are not routinely acknowledged, let alone, disclosed. For one, there are significant financial conflicts that have nothing to do with taking money from industry: “Many nutrition scientists and experts write books about their opinions and diet preferences. Given the interest of the public in this topic, books about nutrition, diets, and weight loss often appear on best-selling lists, even though most offer little to no evidence to support their frequently bold claims.” Furthermore, “Financial conflicts of interest can also appear in unexpected places. For example, many not-for-profit nutrition initiatives require considerable donor money to stay solvent. Public visibility through the scientific literature and its reverberation through press releases, other media coverage, and social media magnification can be critical in this regard.” Even these financial conflicts can perhaps be dealt with through established disclosure norms. But conflicts can get even more complicated when it starts reflecting researchers’ own personal views and biases:: “Allegiance bias and preference for favorite theories are prevalent across science and can affect any field of study. It is… Read More »
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