How do you do a Carbohydrate Loading?

Isabel del Barrio 6 min. of reading Running Leave a comment

Carbohydrate loading is a dietary practice used by athletes to boost competition performance by providing proper energy sources through skeletal muscle glycogen content

What is Carbohydrate Loading?

Carbohydrate loading is a type of diet where carb-rich foods are eaten a few days before or just before a competition

This provides energy during long-distance competition, as it helps replenish and load muscle glycogen content.

Long-distance running

Muscle glycogen is the main fuel for muscles to perform daily training as well as competition. Carbohydrates are broken down by the body and converted into glycogen, which is stored in muscles.

Click here to learn more about the role of carbohydrates before, during and after exercise.

What’s Carbohydrate Loading For?

Depleting glycogen stores in the body causes fatigue

To delay fatigue during long-duration competitions, carbohydrates are taken beforehand and during the event. Training increases the glycogen storage capacity in muscles, boosts glycogen metabolic efficiency, and allows for more aerobic work.

Carbohydrates are a main fuel source for the body and essential for endurance athletes

Carbohydrate Loading Protocol

There are 2 protocols for the days leading up to a long-distance competition

The main goal is to produce carbohydrate supercompensation and maximize glycogen stored in muscles in the days before the competition to have greater reserves during the event.

Classic Carbohydrate Loading Protocol

What’s it about?

This protocol involves training with low glycogen stores, as it might promote a stronger training response.

How is it done?

It lasts about 7 days and includes two phases:

3–4 day depletion phase with hard training and low carb intake followed by a
3–4 day loading phase with high carb intake and light training.

However, there’s no evidence that a low-carb diet improves training results or offers benefits as a glycogen depletion phase before carb loading.

In fact, this can hurt performance and increase injury risk when training without enough carbs

Evidence

Some studies showed that several days of low carb intake depleted muscle glycogen and reduced endurance compared to moderate carb intake.

However, following that with a high-carb diet for several days supercompensated glycogen stores and further increased time to exhaustion.

During the loading phase, a high proportion of carbs from various sources is usually consumed. Starches are the most relevant. To some extent, fiber content should be reduced.

Modified Carbohydrate Loading Protocol

What’s it about?

It was developed when well-trained runners managed to supercompensate glycogen stores without a severe depletion or glycogen emptying phase.

How is it done?

The modified protocol involves a gradual reduction in training and a gradual increase in carb intake up to the competition. This protocol is a more practical prep for competitions and helps avoid fatigue during prior training.

Evidence

More recently, muscle glycogen concentrations were measured after 1 and 3 days of rest and high carb intake (10 g/kg body weight per day) in well-trained male athletes, showing increased carb storage in the body.

Recovery After a Marathon

After the marathon, the athlete needs to replenish muscles and glycogen stores since they’ll be depleted due to the body’s extreme energy demands. For better recovery, intake should happen within 2h after the competition to promote better glycogen resynthesis.

Carbohydrate and Protein Shake

Consuming 1.2 grams of carbohydrates per kilogram of body weight is the ideal carb amount to consume after a long-distance competition.

The best choice is high glycemic index carbs so glucose enters the blood faster (a good option is amilopectin as a carb recovery source).

Protein intake in a 1:3 ratio with carbs after competition increases muscle capacity to replenish glycogen stores (Ivy et al., 2002). It’s important that the protein source has a complete amino acid profile and is rich in Branched-Chain Amino Acids (BCAAs) and Glutamine, like Whey Protein Isolate (WPI)

In other words, consuming small amounts of protein, about 0.4 grams per kilogram of body weight, combined with carbs is the ideal nutrition after competition.

Conclusions

Carbohydrates = Energy

Carbs are the most essential nutrient in endurance sports. Since carbs are the main fuel for skeletal muscles, glycogen stores in muscles must always be at proper levels to provide the energy needed to run the 42 km of a marathon.

Supercompensation

Carb loading before competition is a very common practice among endurance athletes to supercompensate muscle glycogen levels and ensure muscles have the right amounts needed during the event.

Recovery

After the race, it’s crucial the runner consumes 1.2 grams of carbs per kilogram of body weight to replenish muscle glycogen stores. Also, consuming a small amount of protein with carbs after exercise will boost muscle glycogen synthesis rates; it’s recommended to combine 0.4 grams of protein per kilogram of body weight with carbs.

Having a solid nutritional planning strategy is vital to get the best possible results in competition

Sources

Osowski, A. Carbohydrate recommendations for marathon runners.
Mueller, A., Reek, A., Schantzen, J. Effects of Carbohydrate Loading on High Performance Athletics.
Marquet, L., A., Hausswirth, C., Molle, O., Hawley, J., A., Burke, L., M., Tiollier, E. Brisswalter, J. Periodization of Carbohydrate Intake: Short-Term Effect on Performance. (2016).
Fogelholm, M., Tikkanen, H., Naveri, H., Harkonen, M.,High-carbohydrate diet for long distance runners a practical view-point. Br J Sports Med. 1989 Jun;23(2):94-6.
Burke, L., M. Nutrition strategies for the marathon : fuel for training and racing. Sports Med. 2007;37(4-5):344-7.