Is metabolically healthy obesity a useful concept?

Obesity poses significant public health concerns, including Type 2 diabetes mellitus, cardiovascular disease and stroke. Although deleterious metabolic profiles typically accompany individuals with obesity, various epidemiological studies have identified a subset of patients with a favourable metabolic phenotype referred to as the metabolically healthy obese. Metabolically healthy obesity is a novel concept that stratifies obese individuals according to their respective metabolic status. It has important implications for healthcare policies, particularly the efficient allocation of resources in the targeted treatment of obesity and prevention of metabolic ill-health. However, conflicting evidence in the literature regarding its risk profile questions its clinical relevance. In addition, the lack of a unified definition of metabolically healthy obesity and agreement on its progression further impede its utility as a stratification strategy. This review aims to describe current concepts of metabolically healthy obesity within the literature, evidence of this metabolic phenotype, the clinical implications of patient stratification and limitations of the concept.