Key Points Question Can a definition of metabolic health be empirically derived that allows to stratify risk of mortality in people with obesity? Findings In this study including data from 386 420 individuals across 2 cohorts, a new definition of metabolically healthy obesity was established. People with a phenotype defined as metabolically unhealthy using this definition had significantly higher hazard ratios for cardiovascular disease mortality and total mortality irrespective of body mass index category, and people with phenotypes defined as having metabolically healthy obesity displayed no increased risk. Meaning A new definition of metabolic health identified in this study may allow to stratify risk of mortality not only in people with obesity but also in people with overweight and normal weight.