Follow me on

Etiological Assessment of Obesity: Factors That Affect Physical Activity

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 physical activity. Once we have established that weight gain in a given individual is not primarily driven by a change (decrease) in metabolic requirements, or primarily driven by ingestive behaviour, we turn to the issue of a decrease in physical activity as a drier of weight gain: Barriers to Physical Activity As with caloric intake, activity‐related caloric expenditure can vary from virtually zero (as in a bedridden individual) to several thousand calories a day (as in a competitive athlete). In considering physical activity, it is important to note that in sedentary individuals, the majority of activity thermogenesis results from non‐exercise activity thermogenesis (NEAT) simply from performing the acts of daily living, walking, posture and fidgeting. Any reduction in NEAT, even with no change in planned exercise frequency, duration or intensity, would result in reduced energy requirements. Evidence suggests that some individual’s resistance to weight gain is linked largely to their innate ability to spontaneously increase NEAT to defend against caloric excess. As with nutrition, the factors that determine physical activity can be divided into four domains: socio‐cultural factors, biomedical factors, psychological factors and medications. Determining which of these domains is predominantly responsible for reduced physical activity or sedentariness can allow the clinician to specifically address those barriers in the management plan. We will consider each of these factors in subsequent posts. @DrSharma Edmonton, AB

Full Post

Factors That Can Affect Ingestive Behaviour: Drugs and Medications

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, this post focusses on medications: Medications and Drugs That Affect Hunger and Appetite A wide range of medications and illicit drugs can promote hunger and appetite. These include some oral anti‐diabetic agents, antidepressants, atypical antipsychotics, anticonvulsants, certain hormonal preparations including corticosteroids and oral contraceptives, as well as the medicinal and recreational use of marihuana. Alcohol and other mind‐altering drugs can also promote over‐eating by increasing appetite, reducing dietary restraint and promoting disinhibition. Patients presenting with weight gain and obesity need a careful review of their medication and substance abuse history. Commentary: Obviously this a complex topic as the number of medications and recreational substances that can affect appetite and eating behaviour is long. Nevertheless, assessing the possibility that a change in appetite and weight gain are due to this factor is an essential part of clinical assessment. @DrSharma Edmonton, AB

Full Post

Factors That Can Affect Ingestive Behaviour: Psychological or Hedonic 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: Psychological or Hedonic Factors In contrast to hyperphagia resulting from physical hunger, over‐eating for emotional reward or as a coping strategy is regulated by the hedonic system and has little to do with the body’s real or perceived need for calories. The range of psychological or emotional factors that can initiate and influence eating encompass virtually the entire range of emotional responses including stress, frustration, loneliness, anxiety, anger, disgust, fear, grief, joy, relief, all of which can significantly alter dietary restraint or promote disinhibition. Typically, hedonic hyperphagia is associated with the selection and consumption of highly palatable energy‐dense ‘comfort’ foods, although homeostatic hyperphagia also tends to be associated with the preferential consumption of palatable foods. In addition to simple ‘emotional’ over‐eating, specific psychiatric conditions that affect food intake or can pose important barriers to maintaining a healthy diet must be considered. Increased appetite is a feature of atypical depression and can be interpreted as ‘self‐medicating’ with food – particularly in cases where these foods affect the serotonergic and reward systems to improve mood. Binge eating, night eating and other abnormal eating behaviours must also be seen in the context of underlying emotional or psychological processes that are distinct from homeostatic ingestive behaviour. Other mental health conditions that can significantly affect eating include attention deficit disorders, post‐traumatic stress syndrome, sleep disorders, chronic pain, anxiety disorders, addictions, seasonal affective disorder and cognitive disorders. Particularly sleep deprivation has been associated with increased appetite and ingestion of highly palatable snacks as well as increased risk for diabetes. Patients with obesity resulting from emotional eating or hedonic hyperphagia are most likely to benefit more from psychological and/or psychiatric interventions rather than simply from dietary counselling. Commentary: Although for didactic and practical purposes I find it helpful to distinguish between what I have referred to as “homeostatic” vs. “hedonic” hyperphagia, it is important to note that at a physiological level, the distinction between the “homeostatic” and “hedonic” pathways is not as clear cut as is often assumed. In fact, there is close and complex cross talk between these pathways. For example, hunger, a feature of the “homeostatic” pathway, is also a powerful activator of the “hedonic” pathway, thus leading to seeking out and consumption of caloric-dense… Read More »

Full Post

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

Full Post

The Canadian Obesity Network Is No More – Long Live Obesity Canada!

Over a decade ago, together with over 120 colleagues from across Canada, representing over 30 Canadian Universities and Institutions, I helped found the Canadian Obesity Network with the support of funding from the Canadian National Centres of Excellence Program. Since then the Canadian Obesity Network has grown into a large and influential organisation, with well over 20,000 professional members and public supporters, with a significant range across Canada and beyond. During the course of its existence, the Network has organised countless educational events for health professionals, provided training and networking opportunities to a host of young researchers and trainees, developed a suite of obesity management tools (e.g. the 5As of obesity management for adults, kids and during pregnancy), held National Obesity Summits and National Student Meetings. raised funds for obesity research, the list of achievements goes on and on. Most importantly, the Network has taken on important new roles in public engagement, voicing the needs and concerns of Canadians living with obesity, and advocating for better access to evidence-based prevention and treatments for children and adults across Canada. To better reflect this expanded mission and vision, the Board of Directors has decided to convert the Canadian Obesity Network into a registered health charity under the new name – Obesity Canada – Obésité Canada. So with one sad eye, I look back and hope that the Canadian Obesity Network rests in peace – Long Live Obesity Canada! @DrSharma Edmonton, AB

Full Post