The body constantly consumes energy, and carbohydrates are a necessary nutrient involved in the process. Ingested carbohydrates are stored in the muscles and liver as glycogen and burned as fuels during exercise. In the 1980s, two studies found ingestion of carbohydrates during exercise improved athletic performance.1,2 Recently, various benefits of carbohydrates in sports nutrition have been revealed. Although some effects are still unclear, intake of appropriate carbohydrates is very important.
In a pre-workout setting, carbohydrate loading is a well-known strategy for endurance athletes such as marathon runners, bicycle racers and swimmers. These athletes ingest carbohydrates before workouts to maximize the storage of glycogen in the muscle and liver.
In literature focused on intra-workout behavior, the effects of carbohydrate intake during exercise were investigated. In several studies, the group ingesting carbohydrates during endurance exercise showed significantly higher performance than the group with no carbohydrate intake.3,4 The recommended dose depends on duration of exercise, thus the recent guidelines introduce the optimal amounts of carbohydrates for each duration.5,6
Previously, most studies on carbohydrate ingestion for sports nutrition were conducted using simple carbohydrates. However, there are considerations when it comes to simple carbohydrates such as glucose, sucrose and fructose. These solutions tend to have high osmolality due to low molecular weight, and may cause abdominal discomfort due to delayed gastric emptying. In addition, these carbohydrates are sweet and, therefore, can be undesirable to consume in large amounts. For these reasons, high molecular weight (HMW) carbohydrates are starting to attract attention.
For more information on formulating with carbohydrates for sports nutrition, download INSIDER’s Sports Performance Digital Magazine.
Hiroki Himeno received his doctorate in materials science from the Japan Advanced Institute of Science and Technology. He worked at National Institute of Advanced Industrial Science and Technology (AIST) from 2015 to 2016. He currently works at Glico Nutrition Co. Ltd. in the fine chemicals sales department.
- Coyle EF et al. “Carbohydrate feeding during prolonged strenuous exercise.” J Appl Physiol. 1983;55:230-235.
- Coggan AR et al. “Reversal of fatigue during prolonged exercise by carbohydrate infusion or ingestion.” J Appl Physiol. 1987;63:2388-2395.
- Nicholas CW et al. “Influence of ingesting a carbohydrate-electrolyte solution on endurance capacity during intermittent, high-intensity shuttle running.” J Sports Sci. 1995;13:283-290.
- Febbraio MA et al. “Effects of carbohydrate ingestion before and during exercise on glucose kinetics and performance.” J Appl Physiol. 2000;89:2220-2226.
- Louise MB et al. “Carbohydrates for training and competition.” J Sports Sci. 2011;29:S17-S27.
- Asker J. “A Step Towards Personalized Sports Nutrition: Carbohydrate Intake During Exercise.” Sports Med. 2014;44:S25-S33.