Figure 1.

Metabolically healthy obesity (MHO) vs. metabolically unhealthy obesity (MUHO). In comparison with lean metabolically healthy subjects, those with MHO have increased adiposity and BMI, but with reduced systemic inflammation and retained insulin sensitivity, thus defining them as not having metabolic syndrome (MetS). MHO subjects have elevated subcutaneous white adipose tissue (WAT) levels, without excessive accumulation of visceral fat. Their adipokine profile is similar to lean subjects, but with increased leptin, resistin, and FGF21, and decreased adiponectin, which limits their risk of developing type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD) in the short term. By contrast, those with MUHO exhibit elevated insulin resistance and systemic inflammation in addition to increased adiposity and BMI over lean controls, contributing to MetS. MUHO individuals have excess subcutaneous and intra-abdominal adipose tissue, with increased hepatic fat and fat distributed amongst other visceral organs. This leads to a dysfunctional adipokine profile, characterized by reduced adiponectin and omentin, with further elevated leptin, resistin, FGF21, and cytokines when compared to lean controls. Thus, MUHO subjects are at risk for developing T2DM and CVD.