To ensure that elite adolescent athletes meet their unique training, growth and maturation demands, it is imperative to have access to valid measures of energy intake. Contemporary methods demand close attention-to-detail, meaning that athletes often do not fully adhere to real-time protocols. This study represents the first investigation of a real-time dietary assessment designed using a comprehensive behaviour change framework (COM-B). In a crossover design, 12 elite adolescent male rugby players recorded their energy intake via an estimated food diary (est-FD) and photography-based mobile assessment ('Snap-n-Send'), combined with a 24-h dietary recall interview. Two 4-day assessment periods were divided into three separate recording environments: 96 h free-living and researcher-observed; 72 h free-living and 10 h researcher-observed. Assessment periods were one month apart. All foods and beverages were provided and weighed by the research team to quantify actual intakes. 'Snap-n-Send' reported a small mean bias for under-reporting across 96 h (-0.75 MJ day-1; 95% confidence interval [CI] for bias = -5.7% to -2.2%, p < .001), 72 h (-0.76 MJ day-1; 95% CI for bias = -5.6% to -2.1%, p = .004) and 10 h (-0.72 MJ day-1; 95% CI for bias = -8.1% to -0.1%; p = .067) environments. The est-FD reported a moderate mean bias for under-reporting across 96 h (-2.89 MJ day-1; 95% CI for bias = -17.9% to -10.2%; p < .001), 72 h (-2.88 MJ day-1; 95% CI for bias = -17.9% to -10.1%; p < .001) and 10 h (-2.52 MJ day-1;-26.1% to -5.3%; p = .023) environments. Results evidence the ability of 'Snap-n-Send' to accurately assess the diet of elite adolescent athletes, signalling the exciting promise of this comprehensive and theoretical behavioural approach within valid dietary assessment.
Keywords: Energy intake; behaviour change; ecological momentary assessment; elite adolescent athlete; rugby; validity.