The Ironman triathlon is an ultraendurance event that requires specific training and individually tailored nutritional practice. Carbohydrate depletion and dehydration are likely causes of fatigue, yet hyponatremia has been highlighted as a major concern during such events. As a consequence, triathletes are recommended to evaluate fluid losses during practice sessions and develop personal fluid replacement programs to ensure fluid balance. With regard to dietary preparation there are new methods of glycogen supercompensation, recommendations for improving fat oxidation while maintaining endogenous glycogen stores, and evidence aligned to the benefit of consuming combined carbohydrate intake during the race to increase exogenous carbohydrate oxidation rates. Although this review evaluates recent findings in order to make nutritional recommendations, it requires, at times, the generalization from a variety of endurance/ultraendurance studies. This highlights the need for further research within the triathlete population in order that future recommendations are sport-specific and therefore more reliable.
Corresponding author Anna Robins, MD, School of Community, Health Sciences and Social Care, University of Salford, Frederick Road, Salford M6 6PU, UK. E-mail: A.Robins@salford.ac.uk