Nutrition status and carbohydrate intake in relation to training volume of 421 young elite German athletes

INTRODUCTION: Young athletes often face the challenge to meet the recommended nutrient and energy intake for sports performance and development. Training demands vary throughout the season wherefore nutrient intake, especially the carbohydrate (CHO) intake, has to be adjusted in respect to training volume and intensity (Burke 2011). The purpose of this study was to investigate the nutritional status in regard to the training demands of young elite German athletes from 28 different sports using a 7-day food record in parallel with a 7-day activity record. METHODS: A total of 728 young elite athletes (15.4±1.9 yrs) completed the validated food and activity protocol (Koehler et al. 2010). Misreporting was assessed by the ratio of energy intake to energy expenditure and misreported protocols (n=307) were excluded from analysis (Black 2000). The food records of 421 remaining young athletes (15.4±1.9 yrs; 213 females, 207 males) were analyzed concerning energy and macronutrient intake using the German food database (BLS 3.01). Energy expenditure was calculated using predictive equations. RESULTS: Mean energy intake was 2746±540 kcal/d (females: 2326±385; males: 2972±664) and estimated energy expenditure averaged 2643±630 kcal/d (females: 2442±281; males: 3061±564). Overall macronutrient intake averaged 5.4±1.4 g/kg body weight (BW) CHO, 1.6±0.4 g/kg BW protein and 1.7±0.5 g/kg BW fat. Regarding gender differences and daily training volumes of <1, 1-3h, >3h, CHO intake for the male athletes was 5.2±1.2, 5.7±1.4, 6.1±1.7 g/kg BW and for the female athletes was 5.1±1.1, 5.2±1.3, 6.6±1.7 g/kg BW, respectively. Energy balance for the different training volumes was +6, -104, -228 kcal/d (male athletes) and +7, -147, -127 kcal/d (female athletes). CONCLUSION: Energy balance and CHO intake recommendations (5-7g/kg BW/d) (Burke 2011) were met, when the average daily training volume was <1h, indicating a reduced training phase. With an increased training volume of 1-3 hours/d, energy and CHO requirements (6 10g/kg BW) (Burke 2011) increase and these were not met by the young male and female athletes. When the average daily training volume increased to >3 hours, energy balance as well as increased CHO requirements were not met by both genders. As a consequence, strategies for young athletes have to be developed to meet nutrient requirements when performing a high training volume. Sustained periods within negative energy balance can result in severe physiological concerns regarding growth, development, the menstrual cycle and bone health. Young elite athletes need to learn general nutritional and timing strategies according to the individual schedules starting already from a young age in order to be well prepared when training volumes and demands increase with age.