Metabolic heterogeneity of obesity.

Metabolically healthy versus unhealthy obesity shows substantial heterogeneity in insulin sensitivity, with metabolically healthy obesity defined by normal fasting glucose, oral glucose tolerance, lipids, and intrahepatic triglycerides.

• Why it matters: This matters because multi-organ insulin resistance drives obesity-related complications, yet people with obesity vary widely in metabolic risk and in how they respond to weight loss.
• What they did: This Review synthesizes metabolic differences across cellular, organ-system, and systemic levels between metabolically healthy and metabolically unhealthy obesity, including heterogeneity in therapeutic effects of weight reduction.
• The result: Improved understanding of these divergent groups and physiological responses to weight loss may help identify factors linking excess adiposity to metabolic dysfunction and disease.