Energy, macronutrient and water intake during a mountain ultramarathon event: The influence of distance. A Spanish group has examined the supply of energy and fluid on 3 different runs over 44km, 67km and 112 km. It showed that the route length had no influence on the supply of energy and carbohydrates.
Unlike theotherroute lengthsforthe runnersin the ultramarathonmore fat, butdrank lessfluidthan therunner onthe otherroutes. The results can be found under https://pubmed.ncbi.nlm.nih.gov/28322630/