Obesity Is a Disease

Excerpt

Although obesity is recognised as a risk factor for adverse health outcomes and patients affected by obesity are encouraged to lose weight, obesity remains undertreated in clinical practice because it is not yet accepted as a distinct disease entity. If clinicians can convince themselves that obesity is a disease requiring treatment, the health benefits of intentional weight loss strategies can be harnessed more efficiently. Obesity is primarily a disease of subcortical brain regions which is characterised by the pathognomonic symptoms of excessive hunger and/or reduced satiation after a meal and the pathognomonic sign of increased adiposity. Weight gain accompanying the onset of craniopharyngiomas in children provides a striking clinical example of the rapid onset of obesity when subcortical brain networks are interrupted by the tumour itself and/or as a consequence of its treatment. The aetiology of obesity remains poorly understood, although it is now recognised that polygenic obesity accounts for the majority of cases, with complex gene-environment interactions ultimately resulting in a net positive energy balance and adipose tissue expansion. Importantly, many obesity complications including hypertension, type 2 diabetes mellitus, obstructive sleep apnoea, and non-alcoholic fatty liver disease are reversible with intentional weight loss. This provides both a strong rationale and opportunity to improve our understanding of obesity as a disease and ultimately to increase the appropriate delivery of intentional weight loss strategies, the prototypical form of which is metabolic surgery, in clinical practice.