Why glycogen replenishment matters

Why you should Eat your Carbs?

Hard training depletes muscle and liver glycogen, the primary fuel for high-intensity and repeated efforts. Research from PubMed reviews and meta-analyses shows that post-exercise carbohydrate intake is the key driver of glycogen resynthesis, with the fastest restoration occurring in the first 0–4 hours after exercise.

If glycogen is not replenished:
Incomplete restoration leads to reduced performance in subsequent sessions, earlier fatigue, poorer training quality, and slower recovery—especially when workouts are close together (same day or next day). Delaying carbohydrate intake significantly reduces the rate of glycogen resynthesis, making it harder to sustain volume and intensity.

If glycogen is replenished efficiently:
Adequate carbohydrate intake (≈ 1.0–1.2 g/kg/h in short recovery windows) restores glycogen faster, supports repeat performance, stabilizes energy levels, and improves overall training adaptations. Adding protein mainly supports muscle repair; its effect on glycogen is modest unless carbohydrate intake is low.

Bottom line:
Rapid refuelling matters most when recovery time is short; when ≥24 h is available, total daily carbohydrate intake is more important than exact timing.