Development, content and planned evaluation of a behavioural support intervention to reduce ultraprocessed food intake and increase physical activity in UK healthcare workers: UPDATE trial stage 2 study protocol.

introductionDiets high in ultraprocessed food (UPF) are associated with poor health outcomes and weight gain. Healthcare workers are particularly at risk of consuming diets high in UPF due to erratic work patterns, high stress and limited access to fresh food at work. Despite this, no interventions to date have specifically targeted a reduction in UPF intake in healthcare workers. METHODS AND ANALYSIS: This article describes the development and content of a 6-month behavioural support intervention targeting a reduction in UPF intake in UK healthcare workers. The intervention was offered to all participants who took part in the UltraProcessed versus minimally processed Diets following UK dietAry guidance on healTh outcomEs trial-a two-stage study in which Stage 1 was a controlled-feeding crossover randomised controlled trial of provided UPF versus minimally processed food (MPF) diets (published previously) and was completed before the start of Stage 2. Stage 2, reported here, aimed to support participants to reduce their UPF consumption, increase MPF and increase physical activity in real-world settings. The intervention was developed using the behaviour change wheel framework, which systematically links behavioural diagnoses to intervention functions, incorporating the capability, opportunity and motivation model for behaviour change. It included tailored one-to-one and group support sessions, bespoke digital and print resources and a mobile-optimised website. The detailed description is intended to support future replication and adaptation. The acceptability and feasibility of the intervention will be assessed using quantitative and qualitative data in a future paper. ETHICS AND DISSEMINATION: Sheffield Research Ethics Committee approved the trial (22/YH/0281). Findings will be disseminated through peer-reviewed publications, conference presentations and summaries shared with participants and stakeholders. TRIAL REGISTRATION NUMBER: NCT05627570.