# The Carb Revolution Reshaping Ultrarunning Performance
Ultrarunners are breaking records at an unprecedented rate, and carbohydrates appear to be the fuel driving this shift. Coach and runner David Roche has become a vocal proponent of high-carbohydrate fueling strategies for endurance athletes tackling distances beyond the marathon, challenging decades of conventional wisdom about fat adaptation and ketogenic approaches.
The traditional ultrarunning narrative emphasized training the body to burn fat efficiently over long distances. Runners would reduce carbohydrate intake, believing fat adaptation would provide unlimited energy for 50-mile, 100-mile, and multi-day races. This strategy dominated ultrarunning culture for years, with coaches recommending low-carb training blocks and limited carbohydrate consumption during events.
Roche's approach flips this model. He advocates for consistently high carbohydrate intake both during training and racing, backed by mounting evidence that the human body performs better with readily available glucose rather than relying solely on fat metabolism. This strategy aligns with emerging sports science showing that carbohydrates fuel the central nervous system more efficiently, preserve muscle tissue during ultra-endurance efforts, and maintain cognitive function when fatigue sets in.
The timing matters here. Recent ultrarunning victories have coincided with athletes adopting higher carbohydrate protocols. Runners fueling with 60-90 grams of carbohydrates per hour during races now represent a significant portion of top finishers. This contrasts sharply with older approaches where ultrarunners often consumed minimal calories, relying on slower metabolic rates and fat stores.
Carbohydrate absorption during prolonged exercise remains complex. The intestines can only process so much glucose simultaneously, typically maxing out around 90 grams per hour when athletes use multiple carbohydrate sources. Exceeding this threshold causes gastrointestinal distress. However, training the gut through consistent practice allows runners to absorb carbs more efficiently and tolerate higher intake levels during actual races.
Roche's methodology extends beyond race day fueling. He structures training runs to include adequate carbohydrate availability, meaning ultrarunners eat normally rather than attempting long runs in a fasted or depleted state. This preserves training quality, reduces injury risk, and teaches the body to utilize carbohydrates effectively at race intensity.
The shift reflects broader changes in endurance sports science. Studies examining elite distance runners, cyclists, and triathletes show performance improves when athletes maintain sufficient glycogen stores and consume carbohydrates during efforts lasting longer than two hours. Ultrarunning, taking 8 to 20-plus hours, absolutely fits this profile.
This doesn't mean abandoning fat as a fuel source. Ultrarunning still relies heavily on fat oxidation during endurance efforts. The key distinction involves ensuring carbohydrates remain available alongside fat metabolism rather than forcing athletes to operate primarily on fat stores.
For ultrarunners considering this approach, the practical implications matter. Races now require different fueling strategies, with emphasis on real food sources, gels, and sports drinks rather than minimal nutrition. Training must adapt too, incorporating carbohydrate consumption during long runs to practice fueling and prepare the digestive system.
The record-breaking pace in ultrarunning over the past five years suggests this high-carbohydrate paradigm works. As more runners adopt these strategies and see performance improvements, the old fat-adaptation dogma continues losing ground to evidence-based fueling protocols prioritizing carbohydrate availability.