Fuelling at 120 g of Carbohydrate per Hour: Next Level Endurance Nutrition

Next Level Endurance Nutrition

In endurance sport, the margin between a good and exceptional performance isn’t just about how hard you train, but how well you fuel. 

One of the cutting-edge strategies used in elite sport in the modern era explores ingesting 120g of carbohydrate per hour during long, intense efforts (+2.5 hours). Anecdotal athlete practice and research shows elites moving well beyond the traditional 60–90 g/hr benchmark.

What’s behind this shift? Two core findings: first, data from a major Ironman showed that athletes consuming around 120 g/hr finished fastest in the cohort. Second, a controlled study in mountain marathon runners found that the 120 g/hr group had significantly lower markers of muscle damage versus the 60–90 g/hr groups. But it’s not all straightforward.

A further trial found that at 120 g/hr, the amount of fat that an athlete can burn as a fuel dropped compared to 90 g/hr, suggesting that more carbs don’t always deliver a net performance benefit. It just changes the contribution of the energy source in accordance with availability, without offering a performance advantage.

So, what does this mean for athletes and coaches?

Only pursue 120 g/hr if you're training or your race demands it. Examples include long duration, high intensity or racing with minimal recovery windows ie. stage racing. The gut must be trained, as intestinal transporters adapt over time to tolerate higher rates of absorption. Hydration also becomes critical; when perspiration rates and environmental temperatures are high, attempting 120 g/hr without adequate fluid risks gastrointestinal distress.

In short, 120 g/hr is a powerful tool allowing athletes to preserve their endurance battery, but one that should be deployed with discipline, periodised gut training, and a strong hydration strategy. Only then does it transition from a number on paper to a performance driving strategy.