The hormone epinephrine keeps the insulin level from rising too high in response to glucose in the blood. This explains why consuming food high in GI during and the next 3 hour after exercise, doesn't increase your body fat. All the carbs goes to restore the glycogen stores. Glucose goes into muscle glycogen and fructose goes into liver glycogen. It wouldn't be wise to simultaneously releasing fatty acid into the blood and transferring it back into the fat cells.
Nature is very logical.
Several hours afterwards, the protein synthesis becomes normal and the body begin to repair and rebuild itself. During sleep the growth hormone is released. As mentioned earlier, the growth hormone release fatty acid into the blood. The use of fatty acid is increased and the body seems to relay mainly on fat as energy during rebuilding. If an exerciser makes the mistake of taking sugar within the three hours before exercise, before insulin secretion is suppressed, it will stimulate insulin to pour forth, and hypoglycemia then becomes likely.