In healthy male rats, consumption of a high-carbohydrate diet for 6–48 hours following a single bout of endurance exercise reduces insulin-stimulated glucose uptake in skeletal muscle, and this reduction occurs independently of muscle glycogen supercompensation.

After exercise, muscle becomes more sensitive to insulin and takes up more sugar. But when a high-sugar diet is eaten soon after, excess sugar gets diverted into a different pathway that adds a chemical tag to key insulin proteins. This tag blocks the signal that tells muscle cells to bring sugar transporters to the surface, so less sugar enters the muscle even when insulin is present.