Weight Gains Across Adulthood-The ELSA-Brasil Study

Our objective was to describe weight, fat mass, skeletal mass and waist gains across the adult lifespan. We analysed data from 11 611 participants in the Brazilian Longitudinal Study of Adult Health, aged 35-74 years at baseline and followed from 2008 to 2024. Anthropometric measurements were performed at all visits, and bioimpedance at follow-up visits. Weight at age 20 was self-reported. Age-related changes in weight, fat and muscle mass and waist circumference were estimated using generalised estimating equations with restricted cubic splines. Participants' weight increased a mean of 15 kg from age 20-60, when weight peaked. Most of this increase (50%) occurred before age 35. While obesity manifested mainly in later life, maximum annual weight gains were seen up to age 40-45. Gains then tapered, and weight stabilised across ages 55-65, and then decreased at older ages. While fat and muscle mass followed trajectories similar to that of weight, waist circumference increased steadily up to age 75. Approximately half of the difference in adult weight occurred before age 35. Population-based and clinical interventions to limit weight gain in young adulthood, if effective, could have a major impact on the incidence and long-term burden of obesity.