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.

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