Adolescent male academy footballers often fail to meet nutritional recommendations, placing them at increased risk of compromised growth, health, and performance. Guided by the Behaviour Change Wheel, this study aimed to select and specify dietary behaviours to underpin a sport nutrition service within an English Football League Championship academy. Two Nominal Group Technique (NGT) workshops (mean duration = 2 h 20 min) were conducted with four experienced sport nutritionists, three of whom were currently employed at the club, and one recently employed. Participants generated, ranked, and refined behaviours through structured group discussion, and a follow-up questionnaire. Audio data were descriptively analysed to provide contextual insight into behaviour selection and prioritisation. Twenty-four behaviours were generated, from which a prioritised top 10 were identified. The three highest-ranked behaviours were: (1) consuming ≥ 3 main meals (≥ 900 kcal or 13 kcal·kg⁻¹) and 2 snacks daily (≥ 350 kcal or 5 kcal·kg⁻¹); (2) consuming ≥ 3 carbohydrate portions (40–50 g or 0.5–0.75 g·kg⁻¹) per main meal, and ≥ 1 per snack; and (3) consuming a protein portion (25–30 g or 0.4 g·kg⁻¹) at ≥ 4 eating occasions daily. Collectively, these behaviours formed the “meal frequency and portion size guidance.” Additional behaviours ranked within the top 10 included fruit and vegetable intake, attendance at club-provided meals, hydration practices, and cooking from the club recipe app. Practitioners reported challenges conceptualising behaviours, often defaulting to macronutrient prescriptions, and found prioritisation difficult given the number of valuable behaviours identified. Nonetheless, the iterative NGT process facilitated consensus and provided actionable, evidence-based nutritional guidance. This study demonstrates the suitability of the NGT for co-producing and prioritising dietary behaviours in male academy footballers. The approach effectively structured practitioner insights to identify priority areas for sport nutrition service delivery. However, the time-intensive nature of the behavioural analysis highlights the need for greater behavioural science capability within sport nutrition practice. Defining what athletes should do, rather than just focusing solely on nutrient-based prescriptions, is essential for designing effective, theory-informed behavioural interventions. These findings provide a foundation for designing targeted interventions to support the health, wellbeing, and performance of male academy footballers.
Roe et al. (Sun,) studied this question.