(A) Shown is the observed percent weight loss over 15 years for all participants by treatment group and for the subsets of participants who achieved <5% or ≥5% weight loss at Year 1. Data shown are Mean ± 95% Confidence Intervals (CI). (B) Shown are the observed percentages of participants by treatment group achieving ≥5% weight loss yearly during Years 2–15 among participants who achieved ≥5% weight loss at Year 1. Data shown are Mean ± 95% CI. Sample sizes: Metformin Year 1: 289, Year 5: 247, Year 10: 236. Year 15: 172. Intensive Lifestyle: Year 1: 640, Year 5: 540, Year 10: 491, Year 15: 373. Placebo: Year 1: 137, Year 5: 110, Year 10: 104, Year 15: 92.