Metabolically healthy obesity is transient

Being obese but metabolically 'healthy' (MHO) is uncommon in population data (about 9–14% by strict definitions) and tends to convert to metabolically unhealthy obesity over time; cohort studies and a synthesis suggest most MHO cases become unhealthy within decades. That instability weakens claims that obesity is harmless for a substantial share of people. — This reframes debates about 'Healthy at Every Size' from a values discussion into an empirical question with consequences for public‑health guidance, clinical screening, and advocacy messaging.