Re:Mission study. Evaluating the NHS Low Calorie Diet pilot - an overview of service user data collection methods

Introduction: The National Health Service (NHS) Low Calorie Diet (LCD) pilot programme aimed to support people with type 2 diabetes (T2DM) to lose weight, reduce glycaemia and potentially achieve T2DM remission using total diet replacement alongside behaviour change support. The Re:Mission study seeks to provide an enhanced understanding of the long-term cost-effectiveness of the programme and its implementation, equity, transferability and normalisation across broad and diverse populations. This article presents an overview of the methods used in the Re:Mission study. Methods and analysis: A mixed method approach was used to draw together service user insights from across longitudinal and cross-sectional online surveys and semi-structured interviews supported by a modified photovoice technique. Insights were captured from active service users across the three phases of the programme (total diet replacement, food reintroduction and maintenance) in addition to those discharged prematurely. Survey data were analysed using descriptive statistics and qualitative data were thematically analysed and interpreted through a realist informed lens to understand which aspects of the service work and do not work, for whom, in what context and why. Results: Results from the study are presented elsewhere, with recommendations for policy practice and research.