Rising rates of adiposity in the young pose one of the greatest threats to future population burden of cardiovascular disease. Understanding the contribution of genetic and early-life influences to adiposity profiles in young adulthood – when the first signs of subclinical cardiovascular disease commonly appear – are vital if effective lifetime prevention strategies are to be developed. This data note documents the extensive range of genotypic and phenotypic data available from a London-based sub-study of the long-running Avon Longitudinal Study of Parents and Children (ALSPAC)—the ‘ALSPAC in London’ Study—in which extensive adipose and cardiovascular phenotyping was carried out in participants recruited based on a genetic predisposition to obesity.