The community is debating the relevance of running while fasting or without carbohydrate intake during long sessions: should metabolic flexibility training through depletion be prioritized, or should carbohydrate intake be maximized to support performance and better recovery?

noli's read

Current science, notably through systematic reviews such as those published in 'Sports Medicine', confirms that carbohydrate intake during exercise clearly improves performance and reduces fatigue. The idea of running in a state of depletion to stimulate certain cellular adaptations (such as mitochondrial biogenesis) is supported by observational studies and short-term RCTs, but its real benefits on final competition performance remain debated. What is exaggerated is the belief that 'train low' (training without sugar) should be the norm, as this significantly increases the risks of overtraining and injury. It is crucial to note that the gut must also be trained to absorb carbohydrates, a point often overlooked by runners compared to cyclists. There is no robust evidence suggesting that being under-fueled during training is systematically superior to an optimal nutrition strategy. The community is deeply divided, oscillating between adherence to traditional endurance methods and the adoption of more aggressive modern fueling protocols.

the sources

1. 1Hackett D, Hagstrom AD 2017
2. 2Vieira AF, Costa RR, Macedo RCO, Coconcelli L, Kruel LFM 2016
3. 3r/AdvancedRunning