Increasing engagement with a Mediterranean diet and walking program for healthy ageing: Participant and clinician experiences from the MedWalk trial

OBJECTIVE: To explore participant and clinician experiences of a Mediterranean diet and walking intervention (MedWalk), with a focus on how behaviour change support, communication, and feedback processes influenced engagement. METHODS: A nested qualitative study was conducted within the MedWalk randomised controlled trial. Nineteen intervention-arm participants were purposively sampled to capture variation in behavioural response to the intervention, alongside five clinicians who delivered the dietary, walking, and behaviour change components. Semi-structured interviews were conducted and analysed using reflexive thematic analysis. Participant and clinician transcripts were initially coded separately before themes were integrated across datasets. RESULTS: Four themes were identified: (1) learning to live well, (2) supported, not directed, (3) tracking progress, seeking feedback, and (4) the power of the group. Participants valued autonomy-supportive communication and credible guidance. Clinicians described intentionally applying MI-consistent relational strategies, including reflective listening to support engagement. A key divergence emerged in expectations around feedback: clinicians emphasised reflective dialogue to evoke self-recognition, whereas participants sought clearer indicators of progress. Group-based walking enhanced social connection and accountability, requiring facilitation to maintain behavioural focus. CONCLUSIONS: Engagement was shaped not only by intervention content but also by how behaviour change support was communicated and enacted. Findings indicate that reliance on reflective, autonomy-supportive communication alone may not meet participants' expectations for feedback, and that integrating explicit, interpretable indicators of progress may strengthen engagement in lifestyle interventions for older adults. PRACTICE IMPLICATIONS: Interventions targeting diet and physical activity should prioritise relational communication skills and incorporate structured approaches to feedback that provide clear, personalised, and interpretable indicators of progress. Group-based components should be intentionally designed and facilitated to support social connection, shared problem-solving, and peer accountability.