becuase you've basically utilized all or much or your readily available energy sources, your blood glucose will be very low and your metabolism is ramped up for several hours following the workout. The carbs will more likely get utilized as fuel rather than stored in this state.
After a hard work out your Glycogen Stores are depleted, If you take in some Protein, Simple Sugars along with some Creatine it will do wonders for your recovery. The simple sugars after the workout will cause your body to release insulin which in turn will help push the protein, creatine and carbs into the muscle.