International Society of Sports Nutrition Position Stand: nutritional considerations for single-stage ultra-marathon training and racing In this opinion, the International Society for Sportstern deities (ISSN) offers an objective and critical review of the literature, which relates to nutritional aspects for training and race in the ultra-marathon. Recommendations for training: Ultra marathon runners should aim to meet the calorie requirements of the training by pursuing an individualized and periodized strategy that includes a varied food first approach. Sportsmen should plan and implement their nutritional strategy with sufficient time to enable adjustments that improve the fat oxidation capacity. The evidence predominantly supports the absorption of a medium to high carbohydrate diet (i.e. \ ~ 60% of energy consumption, 5-8 g × kg-1 × D-1) to mitigate the negative effects of a chronic glycogen emptying through the training. The limitation of carbohydrate absorption before selected exercises with low intensity and / or moderation of daily carbohydrate recording can improve the function of mitochondria and the fat oxidation capacity.Nevertheless, this approach can affect the performance in intensive efforts. Protein recording of \ ~ 1.6 g × kg-1 × d1 is required to maintain muscle mass and support the recovery from training. In a demanding training, however, quantities of up to 2.5 g × kg-1 × d-1 may be required, recommendations for racing: To reduce calorie deficits, runners should try to run 150-400 kcal × H-1 (carbohydrates, 30-50 g × H-1; protein, 5-10 g × H-1) to consume from a variety of low-calorie food. The palatability of foods, individual tolerability and the increasing preference for hearty foods in longer races must be considered.During the race, fluid volumes of 450-750 ml × H-1 (\ ~ 150-250 ml every 20 minutes) are recommended. In order to minimize the likelihood of hyponatremia, electrolytes (mainly sodium) can be needed in concentrations higher than those provided by most commercial products (i.e.,> 575 mg × L-1 sodium). The liquid and electrolyte requirement is increased when working under hot and / or humid conditions. Today’s evidence supports progressive intestinal training and / or low-FODMAP content diets (fermentable oligosaccharide, disaccharide, monosaccharide and polyol) to relieve symptoms of gastrointestinal discomfort during the race. It lacks evidence of support of ketogenic diets and / or ketone esters to improve ultra-marathon performance, requiring further investigations.
The previous evidence supports the strategic use of caffeine to maintain performance in the last racing phases, especially if sleep deprivation can affect the safety of athletes. The whole article can be found under https://jissn.biomedcentral.com/articles/10.1186/s12970-019-0312-9