Exploring the acceptability of a specialist obesity treatment intervention (Fast Track to Health) for adolescents; a mixed-method study.

BACKGROUND: Fast Track to Health was a 12-month intervention for adolescents with obesity and associated complications. Adolescents followed a very low-energy diet (VLED) and intermittent (IER) or continuous energy restriction (CER). This study explored adolescents', parents', and dietitians' perspectives of the intervention. METHODS: A convergent parallel mixed-methods evaluation was conducted. Acceptability questionnaires were collected from adolescents (Week-16: n=113, Week-52: n=88) and parents (Week-16: n=108, Week-52: n=80). Semi-structured interviews were conducted with adolescents (n=14), parents (n=11), and dietitians (n=6) at Week-52. Interview transcripts were thematically analysed. RESULTS: Adolescents rated enjoyability (score 0-100) at Week-16 [Mean (SD) IER: 63.5 (21.1) vs. CER: 65.9 (20.2), p=0.550] and Week-52 [IER: 67.2 (18.1) vs. CER: 61.0 (23.4), p=0.198], showing no significant difference between groups. Most parents reported benefits at Week-16 (IER: 86% vs. CER: 93%, p=0.263) and Week-52 (IER: 79% vs. CER: 83%, p=0.717). Adolescents positively rated their experience with dietitians. Qualitative feedback emphasized the impact of clear dietary advice, easy and frequent access to support, continuity of care, and family engagement. CONCLUSIONS: This evaluation offers insights into a specialised dietary intervention for adolescents. Findings can inform future obesity treatments for adolescents in outpatient tertiary healthcare settings.