Glycogen stores play a crucial role in prolonged exercise performance, especially in the liver. Unfortunately, these stores are limited. Finding efficient ways to replenish them is paramount for peak performance.
In this issue of The Research Desk, we examine a 2025 study looking at different post-exercise carbohydrate consumption strategies for replenishing liver and muscle glycogen stores.
PMID: 40632477
Vitality Takeaway
In this study, trained male cyclists completed a glycogen-depleting endurance protocol, then ingested 1 of 4 recovery drinks immediately and 180 minutes after exercise:
- 60g CHO from Maltodextrin (MAL)
- 60g CHO from Fructose (FRU)
- 60g CHO from Maltodextrin and Fructose (1:1 ratio) (MF)
- 60g Dual Carbs + 30g whey protein (PRO)
Concerning glycogen stores, there were two major findings in this data set. The first was that Liver glycogen concentrations were significantly higher with FRU, MF, and PRO compared with MAL following 5 h of recovery. Second, muscle glycogen concentrations were not different between trials.
The addition of protein did not have any significant effects on liver glycogen replacement. Researchers note that despite increases in aminoacidemia and insulinaemia, the presence of the dual-carbohydrate source alone may have been enough to maximize the storage of glycogen.
The improvements in liver glycogen are related to the metabolism of each source. Glucose is mainly sent into the bloodstream to be used for energy or stored as liver and muscle glycogen, while fructose is mostly processed in the liver, where it’s converted into glycogen or converted into lactate, glucose, or fatty acids.
Researchers also call attention to the minimal effects of the addition of protein on muscle glycogen resynthesis, despite the increased insulin levels. They note that this is in contrast to previous data suggesting that co-ingestion further enhances muscle glycogen storage and may call into question the practical relevance of protein co-ingestion of carbs and protein to promoting muscle glycogen resynthesis.
Replenishing muscle and liver glycogen is widely recognized as a key factor in recovery between training sessions and in sustaining performance during subsequent exercise. This is especially critical for athletes with short recovery windows.
Researchers suggest that the augmented liver glycogen content observed in response to the different trials is likely to be physiologically relevant for prolonged endurance events and would likely provide sufficient energy to sustain an additional ∼2 min of exercise at ∼70% VO2max in well-trained male cyclists. These findings drive home the importance of mixing carbohydrate sources when refueling.
Vitality Application
Glycogen stores play a crucial role in endurance performance. Post-exercise carbohydrate consumption is vital to supporting these concentrations. Further, consuming protein can amplify this process and supply the needed amino acids for muscle recovery.
By supporting fuel sources and muscle recovery, peak performance can be maintained even during the longest events.
Recommendation: Consume 0.5 g of protein/ kg of body weight and 1 g of carbohydrate/ kg of body weight immediately after intense exercise.
Explore the Vitality Encyclopedia to learn more about these topics.
