What fuels intense training? If you’ve ever tried to train during a low-carb diet cycle— or even after one day of low-carb eating— you likely know it’s like dragging a heavy suitcase without wheels across concrete... and you are the suitcase. Part of the drag may be due to lower muscle carb (glycogen) stores.1,2 High-maximal intensity resistance training, in well-trained athletes, uses up as much muscle glycogen in a muscle with low glycogen as a muscle with normal glycogen content— with the same workout.1 But the other drag may be your brain in a relatively glucose-deprived state. Attempts to perform long-term studies comparing low- versus high-carb diets with high-intensity resistance training have failed, simply because the subjects on the low-carb diet couldn’t sustain hard training (relative to those on the higher carb diet).2 Carbohydrate is the substrate that fuels high-intensity training. Period