Abstract
This study investigates whether providing individuals with feedback about their weight status influences long-term health outcomes, specifically the incidence of myocardial infarction (heart attack) over a 13-19 year period. Using data from the UK Biobank, where participants received weight status feedback based on Body Mass Index (BMI) thresholds, the study employs a regression discontinuity design to estimate the causal impact of receiving adverse weight information. The findings reveal that such feedback reduces the risk of myocardial infarction by 0.6 %age points, representing an approximate 18% relative risk reduction. While the magnitude of the effect is modest, the low cost and scalability of information-based interventions suggest a potential value in preventative healthcare. These results contribute to the literature by linking personalised health information not just to behavioural change, but to tangible long-term health outcomes. The study supports the integration of weight feedback into routine screening programmes as a cost-effective strategy to mitigate heart attack risk and improve population health as part of preventative health policy.</p>