Part of a UKRI Transforming UK Food Systems grant, [DIO-Food][1], led by the University of Aberdeen. This project forms Work Package 6 **"HFSS Legislation impacts"**. This work expands the existing FIO Food scope of living with obesity to connect with vulnerable citizens who are facing diet and health inequalities. As the cost-of-living crisis is a dynamic process, we need approaches to timely respond to the emerging ‘crisis’, using the most recent data. **Review of HSFS policy on retail purchase patterns** Lead: Prof. [Michelle Morris][2] In October 2022, legislation came into effect in England that restricts promotion of products High Fat, Sugar or Salt (HFSS) by in-store and online location. Beginning a year on from the legislation’s implementation, this team will analyse population-level supermarket transaction data provided by a large UK retailer to evaluate the impacts of HFSS legislation. This will be the first-ever evaluation of this legislation and comes ahead of proposed implementation in the devolved nations. This, therefore, provides a unique opportunity to conduct an analysis of the impacts for retailers ahead of any new policy changes across the UK. The team will analyse the impacts of the implementation from a health and sustainability perspective, using dietary (Eatwell Guide) and environmental metrics developed with IGD and their INSG. The team will also use highly innovative data products created by Pontin (Eatwell algorithm) and Jenneson (Nutrient Profile Model Calculator) in their analysis, providing insight to retailers that cannot be found elsewhere. DIO-Food Work Package 6 is comprised of 2 parts: 1. Secondary data analysis (retailer data) Contributors: - Professor Michelle Morris - Dr Victoria Jenneson - Dr Francesca Pontin 2. Primary data collection (surveys and interviews) Contributors: - Dr Alison Fildes - Dr Alice Kinninmonth - Dr Emily Ennis [1]: https://www.abdn.ac.uk/rowett/research/dio-food-1857.php#panel1863 [2]: https://environment.leeds.ac.uk/faculty/staff/12192/professor-michelle-morris