Behind the science
Why are carbohydrates important for exercise?
Herbalife 28 September 2024
What are carbohydrates?
Carbohydrates are one of the three macronutrients in the human diet, along with protein and fat. It is the most important source of energy and at least 40% of your daily energy intake should come from carbohydrates. Carbohydrates play an important role in the human body. They deliver energy and are crucial for the brain. During digestion carbohydrates are being broken down and converted to glucose, which is used for energy upon consumption. Any extra glucose in the bloodstream is stored in the liver and muscle tissue (as glycogen) until further energy is needed.
What are the types of carbohydrates?
Carbohydrates can be categorized based on their chemical structure. Understanding the different types of carbohydrates and their roles can help in making informed dietary choices to ensure a balanced and healthy diet.
The main types of carbohydrates are:
- Simple carbohydrates: These carbohydrates consist of one or two sugar molecules. Examples are fructose, lactose, sucrose and glucose. They are in general more easily utilized for energy, causing a more rapid rise in blood sugar and insulin secretion. Simple carbohydrates can occur naturally in food (e.g. in dairy or fruit) or be added to food (e.g. syrups, carbonated beverages). For our health it is recommended to limit the consumption of added sugars.1
- Complex carbohydrates: These carbohydrates composed of many molecules linked in longer chains are often called “complex”. Examples are starches and dextrin, that can be found in for instance grains, pulses and vegetables. Their digestion takes time, as chains must be broken down to free sugar molecules. As a result, in general, blood sugar levels increase gradually over longer period.
- Fibers: Non-digestible carbohydrates that can encourage healthy bacterial growth in the colon and act as a bulking agent and easing defecation.2 Examples are cellulose and pectin.
The best carbohydrate sources, not only provide energy (from carbohydrates), but also deliver other essential nutrients like minerals, vitamins, and fibre. Examples of “good” sources are (unpeeled) fruit and whole grains.
Function of carbohydrates in the body:
One of the primary functions of carbohydrates is to provide energy.
The brain and the red blood cells are especially dependent on glucose as energy source, and can only use other nutrients like fat in extreme circumstances. It is for this reason that at least 130 g of carbohydrates is needed per day.
In addition, carbohydrates provide energy to other cells of our body, including muscle cells. Energy production from carbohydrates is quicker and requires less oxygen than fat. That’s why moderate to high-intensity exercise is mainly powered by carbohydrates and not fat.3,5
Importance of carbohydrates in exercise recovery:
During an intense or long workout, your body uses blood glucose and stored muscle glycogen to provide a fast-acting source of energy. In order to recover and be ready for the next workout, glycogen stores need to be replenished. When fast recovery is needed, a high amount of carbohydrates should be consumed.6,7
In addition, combining carbohydrates with protein could help recover muscle damage, and may facilitate greater training adaptations.6,7
References
1. Stellingwerff, T. and G.R. Cox, Systematic review: Carbohydrate supplementation on exercise performance or capacity of varying durations. Applied Physiology, Nutrition, and Metabolism, 2014. 39(9): p. 998-1011.
2. Burke, L.M., et al., Carbohydrates for training and competition. Journal of Sports Sciences, 2011. 29(sup1): p. S17-S27.
3. Kerksick, C., ,, et al., ISSN Position Stand: nutrient timing. Journal of the International Society of Sports Nutrition, 2017. 5(1): p. 17.
4. Jeukendrup, A., A step towards personalized sports nutrition: carbohydrate intake during exercise. Sports medicine (Auckland, N.Z.), 2014. 44 Suppl 1(Suppl 1): p. S25-S33.
5. ACSM, Joint Position Stand Nutrition and Athletic Performance. Medicine & Science in Sports & Exercise, 2016. 48(3): p. 543-568.
6. Kerksick, et al., ISSN exercise & sports nutrition review update: research & recommendations. J Int Soc Sports Nutr, 2018. 15(1): p. 38.
7. O'Brien, W.J. and D.S. Rowlands, Fructose-maltodextrin ratio in a carbohydrate-electrolyte solution differentially affects exogenous carbohydrate oxidation rate, gut comfort, and performance. American Journal of Physiology-Gastrointestinal and Liver Physiology, 2011. 300(1): p. G181-G189.