Individuals with metabolically healthy obesity (MHO) do not have the metabolic complications usually associated with obesity.

To examine whether youth adiposity, or change in adiposity from youth to adulthood, predicts MHO 20 years later.

A national sample of 2410 Australian participants had height, weight and waist circumference (WC) measured in 1985 (7–15 years old) and 2004–2006 (26–36 years old). A fasting blood sample was taken in 2004–2006. MHO was defined as body mass index (BMI) ≥30 kg m−2, normal fasting glucose (<5.6 mmol L−1), triglycerides (<1.695 mmol L−1), high-density lipoprotein-cholesterol (>1.036 mmol L−1 men, > 1.295 mmol L−1 women), blood pressure (<130/85 mmHg) and no medication for these conditions. Relative risks (RR) were calculated using log binomial regression and expressed per unit of youth BMI (or WC) z-score or change in BMI (or WC) z-score from youth to adulthood, adjusted for sex and youth age.

In total 323 individuals were obese at follow-up, 79 (24.5%) were MHO. Adult MHO was not associated with youth BMI (RR: 1.00, 95%CI: 0.85–1.19) or WC (RR: 0.93, 95%CI: 0.79–1.11). Individuals were less likely to be MHO if they had larger increases in BMI (BMI RR: 0.74, 95%CI: 0.57–0.97) or WC (RR: 0.70, 95%CI: 0.55–0.90) from youth to adulthood.

Change in adiposity from youth to adulthood predicted adult MHO better than youth adiposity alone.