Training HARD is not about who can do the most amount of training, on the least amount of fuel.
All too often athletes become fixated on just one macronutrient.
But it's not about carbohydrates, protein or fat being superior to one another, it's about just eating food, real food. It's also about manipulating your macronutrient intake each day to match your training load and intensity of the session.
As a general rule, the greater the intensity, the greater the need for carbohydrates.