If you reduce the fiber intake then you can eat more protein and carbohydrate without feeling as full
The body tends to use carbohydrate more than fat for high intensity exercise so 1 carbohydrate calorie near the time of exercise will typically improve endurance more than 1 fat calorie near the time of exercise
The body tends to convert carbs to glycogen instead of fat more if they are consumed closer to the time of exercise
Glycogen is how carbs are stored for endurance