Timing Your Carbohydrate Intake for Better Recovery

The ability to train on consecutive days mainly hinges on your recovery capacity. The basics of recovery are well-established: eating, sleeping, and resting.

When focusing on nutrition, the timing of carbohydrate intake post-exercise can further boost recovery.

An Overview of Carbohydrates

Carbohydrates chiefly supply energy to muscles. They are stored as glycogen in muscles and the liver, with total body glycogen reserves ranging from 380-710g of carbohydrate.

After physical exertion depletes glycogen stores, consuming carbohydrates aids the body in re-synthesizing glycogen. The fastest rates of glycogen synthesis occur after exercise.

The swift and effective replenishment of glycogen supports training on several consecutive days (1).

With this knowledge, a recent study investigated the impact of delaying carbohydrate intake following high-intensity interval exercise (HIIE) on performance in HIIE the next day.

Study Exploration

Participants in this study completed 10×2 VO2 max intervals on two consecutive days. Within the first 3 hours after the initial workout, they consumed either a carbohydrate drink or a flavor-matched placebo without carbohydrates.

Carbohydrate intake was balanced between both groups during the 24 hours between sessions. On the second day, participants repeated the VO2 intervals until exhaustion (2).

The “immediate” group is shown with white bars, and the “delayed” group with red.

Javier Díaz-Lara, Elizabeth Reisman, Javier Botella, Bianka Probert, Louise M. Burke, David J. Bishop, Matthew J. Lee. (2024a, September 12). Wiley. Delaying post-exercise carbohydrate intake impairs next-day exercise capacity but not muscle glycogen or molecular responses.

In summary, participants who consumed carbohydrates immediately after the first session completed 5 more intervals than those in the delayed carbohydrate (CHO) group. The immediate CHO group also experienced lower RPE and heart rates (1).

Delaying carbohydrate intake by just 3 hours resulted in a notable difference between the groups, as the CHO group benefited from increased glycogen synthesis immediately post-exercise (2).

Glycogen Synthesis Rates

Immediately after exercise, glycogen synthase, the enzyme responsible for glycogen synthesis, is highly active. This enables rapid glycogen synthesis.

If carbohydrates are ingested right after exercise, glycogen can be synthesized swiftly. Delaying carbohydrate intake reduces glycogen synthase activity and significantly slows glycogen synthesis rates (2).

The following image illustrates this concept.

age taken from Jeukendrup, A., & Gleeson, M. (n.d.). Sports Nutrition (4th ed.).

Optimizing the Rapid Phase of Glycogen Synthesis

Considering the importance of consuming carbohydrates immediately post-exercise, here are practical guidelines for incorporating this into your training.

Consume high Glycemic Index (GI) carbohydrates immediately post-exercise. When optimizing recovery, the first few hours after exercise are crucial for ingesting high GI carbohydrates (2).

The Glycemic Index (GI) measures the rise in blood glucose and insulin when a standard amount of food is consumed. Higher GI indicates faster carbohydrate availability. High-GI carbohydrates increase muscle glycogen by over 50% compared to low-GI foods (1).

Here are common foods ranked by GI:

Gly index (GI) data adapted from Jeukendrup, A., & Gleeson, M. (n.d.). Sports Nutrition (4th ed.)

Consume 1g/kg of high GI carbohydrates each hour for 4 hours post-exercise. This intake rate optimizes glycogen synthesis. For instance, if you weigh 68kg, aim to consume 68g of high GI carbohydrates each hour for 4 hours after exercise.

References

Javier Díaz-Lara, Elizabeth Reisman, Javier Botella, Bianka Probert, Louise M. Burke, David J. Bishop, Matthew J. Lee. (2024a, September 12). Wiley. Delaying post-exercise carbohydrate intake impairs next-day exercise capacity but not muscle glycogen or molecular responses. https://onlinelibrary.wiley.com/doi/pdfdirect/10.1111/cas.14215

Jeukendrup, A., & Gleeson, M. (n.d.). Sports Nutrition (4th ed.)