You Can’t Run a Marathon Without Carbs: The Truth About Fueling for Long Distances

A Battle of Fueling Philosophies
Endurance fueling has long crowned carbohydrates as king, essential for sustaining high-intensity efforts and avoiding "hitting the wall." Decades of research back carb fueling strategies, with elite athletes relying on glycogen and mid-race supplements to maximize performance. However, the rise of low-carb, high-fat (LCHF) diets challenges this norm, with advocates promoting fat as a nearly limitless energy source ideal for slower-paced efforts. While fat adaptation can improve metabolic efficiency, it struggles to meet the energy demands of high-intensity racing. For most, a hybrid approach—training to improve fat oxidation while fueling with carbs on race day—offers the best of both worlds. Ultimately, fueling is personal, and success lies in aligning your strategy with your goals and physiology.