Too Wordy, Too Long and Too Cluttered: User Acceptance Testing, Co-Design, and Early Beta Testing to Adapt the Daily Health Coach for Young Australian Women

Background/Objectives: The Daily Health Coach (DHC) is a 12-week Instagram-based nutrition and wellbeing programme originally co-designed and tested in New Zealand to deliver evidence-based, weight-neutral content on nutrition, movement, body image, and wellbeing. This formative, mixed-methods adaptation study examined the acceptability of DHC New Zealand content for young Australian women and identified refinements to improve relevance, engagement, and safety before effectiveness evaluation. Methods: Using the CODES framework, we conducted three adaptation phases: user acceptance testing, co-design workshops, and early beta testing. Following data-quality screening, 291 young women aged 18–24 years who completed all 12 survey sections were included in Phase 1. Participants rated 84 Instagram-style posts for understanding and usefulness and provided open-ended feedback. Twelve young women participated in co-design workshops, and seven adapted artefacts were beta-tested with eight target users using cognitive walkthrough and think-aloud methods. Quantitative findings were examined descriptively, with sensitivity analyses undertaken to assess robustness to response-quality and sample-composition concerns. Results: Participant-level mean understanding was 3.99 ± 0.75/5, usefulness was 3.89 ± 0.74/5, and the combined score was 7.87 ± 1.47/10. Post-level combined means ranged from 7.66 to 8.11/10; all 84 posts met a ≥7.5 descriptive benchmark adapted from prior message-testing work, although this is an interpretive aid rather than a validated cut-off. Sensitivity analyses showed a similar overall pattern: ratings were higher in a higher-confidence response-quality sample (n = 199; 8.34 ± 1.20/10), while four posts fell marginally below 7.5 when analysis was restricted to participants not reporting Aboriginal and/or Torres Strait Islander identity (n = 101). Qualitative feedback identified six refinement areas: content features, engagement strategies, clarity, educational accuracy, relevance, and miscellaneous concerns. Co-design and beta testing generated four adaptation priorities: tone, design, engagement, and understanding. Conclusions: DHC New Zealand content was generally well understood and favourably rated but required targeted refinement for the Australian context. Findings provide formative guidance for final adaptation and subsequent effectiveness evaluation.