Nigel Mitchell

Designing and implementing successful dietary interventions is integral to the role of sports nutrition professionals. Despite this, no review has evaluated sports nutrition interventions and consequently their active ingredients are not defined. This systematic review aimed to identify the behavioural strategies used in sports nutrition interventions and to explore any relationship between the strategies employed and intervention effects. SPORTDiscus, MEDLINE, CINAHL, PubMed, and SCOPUS were searched for behavioural interventions that aimed to change athletes' dietary behaviour. Behavioural interventions were eligible for inclusion provided pre and post-measures of dietary intake were reported. The protocol adheres to Preferred Reporting Items for Systematic reviews and Meta-Analyses Protocols (PRISMA-P). Each study was coded against the “Template for Intervention Description and Replication” (TIDieR) checklist and the Behaviour change technique (BCT) taxonomy v1. Only 19 BCTs are currently employed within sports nutrition interventions suggesting that 80% of the available BCTs are not being used. Only three studies were theory informed and the standard of reporting across all studies requires substantial improvement. However, the majority of studies reported changes in athletes’ dietary behaviour post-intervention. This review highlights an absence of evidence-informed approaches defining the professional practice of sports nutrition and illuminates a limited application of BCTs within the sports nutrition field. Consequently, the authors provide a framework and guide for intervention development to increase rigour and effectiveness of future sports nutrition interventions. PROSPERO registration number: CRD42018072283.

OBJECTIVES: To determine the neurobiochemical sequelae of oral creatine monohydrate supplementation in active athletes. DESIGN/PARTICIPANTS: Eighteen sportsmen underwent single-voxel proton magnetic resonance spectroscopy of the deep frontal cerebral white matter before and after 5 days of oral ingestion: 12 of 18 swallowed 4 x 5 g creatine monohydrate per day, and the remaining swallowed a placebo. MAIN OUTCOME MEASUREMENTS: Creatine, choline, and N-acetyl spectral resonances were evaluated at both long (135 ms) and short (20 ms) echo times. RESULTS: A mixed-design factorial ANOVA demonstrated no interaction over time in any of the measures (P at least 0.081). CONCLUSIONS: The results suggest that, for the given dosage regimen, ingested creatine augmentation does not alter the magnetic resonance visible creatine pool in the deep frontal cerebral white matter of young active sportsmen.

Objectives: Poor adherence to nutritional guidance by athletes may compromise their health and performance. Enhancing adherence is therefore an important performance and welfare strategy. The aim of this study was to qualitatively explore the barriers and enablers of elite athletes' adherence to nutritional guidelines. Design: Underpinned by our constructionist epistemological position and our relativist ontology, we conducted a qualitative study using focus groups. Methods: We used the Capability, Opportunity, and Motivation Behaviour (COM-B) model and the Theoretical Domains Framework (TDF) to conduct focus group discussions with a purposive sample of 39 UK-based funded athletes (mean age = 23 ± 3.81), participating in either Olympic and Paralympic sport (n = 30) or professional sport (n = 9), who had access to a nutritionist. Data were analysed using reflexive thematic analysis. Results: Athlete adherence to nutritional guidance was seasonal and included inadequate energy intakes and episodes of binge eating. Underpinning these behaviours, athletes' emotional barriers (motivation) are reinforced through their social interactions within the high-performance environment (opportunity) and athletes' training environment limits developmental opportunities for food planning (capability). However, a holistic-developmental approach by the sports nutritionists (opportunity) supports athlete wellbeing and nutritional adherence. Conclusion: These findings advance theoretical understanding of the barriers and enablers of nutritional adherence amongst elite-level athletes in high-performance sport and present a number of significant implications for athlete support personnel seeking to enhance performance in demanding sporting contexts. Drawing on the Behaviour Change Wheel (BCW), recommendations include the need to 1) train and educate sports nutritionists in human behaviour, 2) update regulations for sports nutrition profession practice to acknowledge the skills required to support athletes' emotional wellbeing, 3), educate coaches on the sensitivity of body weight and composition and develop guidelines for monitoring athletes' body weight and composition in sport, 4) persuade influential leaders to develop culture guidelines that shift the performance-narrative of high-performance (i.e., environmental restructuring).

Athlete adherence to nutritional guidance is critical for optimal health and performance, yet little is known about the barriers and enablers to athletes’ dietary behaviours within high-performance sport. To advance understanding, we applied a theoretical lens derived from the Capability, Opportunity, Motivation–Behaviour (COM-B) model and the Theoretical Domains Framework (TDF) to explore the qualitative accounts of sports nutritionists. Five focus groups comprising sports nutritionists working in Olympic and Paralympic sport (n = 14), professional sport (n = 6), or both (n = 6) were undertaken. Thematic analysis was conducted and the interpretations of the findings were guided by COM-B and the TDF. To achieve nutritional adherence, the behavioural analysis identified the need to intervene across all three COM-B components and at least five associated TDF domains (e.g., decision-making processes, reinforcement, social influences, behavioural regulation and environmental context and resource). For the first time, the findings illustrate the complex interplay of the training setting with the capabilities, opportunities, and motivation of the practitioners, athletes and coaches. By applying established behavioural science theories to sports nutrition, the foundations for the development of targeted and multifaceted behavioural interventions addressing athlete dietary adherence in high-performance sport have been laid.