Carbohydrates are made differently. Differences between carbohydrate types are often oversimplified in media, where sugars are portrayed as providing a quick burst of energy while starchier, complex carbohydrates provide a longer-lasting effect on energy provision. But how do these carbohydrates actually differ? Exploring the mechanisms of how they work in the human body helps us make informed choices about what and when to consume each type of carbohydrate.
Simple carbohydrates: fast fuel, short chains
Simple carbohydrates are split into two categories: monosaccharides (one sugar molecule) and disaccharides (two chained together). These carbohydrates provide a quick burst of energy due to their rapid digestion (Fuchs et al., 2016). The rapid digestion can likely be attributed to the small number of molecules chained together. For example, your table sugar used for baking is comprised of a two-sugar chain combining glucose and fructose (Gonzalez et al., 2017).
Fascinatingly, different simple carbohydrates — such as glucose and fructose — do not take the same path in the body. This specific area became highly relevant in sports nutrition during the 21st century, as the development of nutrition knowledge in endurance sports drove performances to the next level. These sugars are digested and absorbed into the bloodstream through different transporters (Fuchs et al., 2019).
Today, it is understood that during demanding exercise, a mix of multiple transportable carbohydrates is essential to improve performance and recovery (Jeukendrup, 2010; Jeukendrup et al., 2026). This is why endurance sports drinks and gels usually combine glucose and fructose — you can get more fuel into your body per hour by using two “roads” instead of one.
However, while sports drinks or gels are essential to keep up with training demands, during recovery and at rest the focus should switch to whole foods such as grains, potatoes, and vegetables.
Complex carbohydrates: the slower, richer foundation
Complex carbohydrates have longer sugar chains and are present in products such as potatoes, grains, and vegetables — dietary staples around the world. While these are starchier than simple carbs, the longer digestion time results in later, but longer-lasting energy release (Fuchs et al., 2025). This is the result of the longer chains, which are time-consuming to break compared to a two-molecule chain, as well as an increase in fiber content in complex carbohydrates.
Fiber can influence satiety, which explains the feeling of fullness people feel after consuming a meal containing complex carbohydrates compared to when they consume a handful of candy (Rebello et al., 2016). Beyond fiber, these products contain an array of vitamins and minerals essential for well-being (Jeukendrup & Gleeson, 2023).
Therefore, foods such as vegetables, grains, and fruits should represent the majority of carbohydrate intake and contribute a large share of daily energy (~50–55% of energy intake from carbohydrates).
So — which type is “better”?
Priority should be given to whole foods containing complex carbohydrates, vitamins, minerals, and fiber. Such products are essential in ensuring overall well-being and provide a platform to achieve high performance in exercise. These can be supplemented by appropriate sports nutrition strategies, including consumption of simple carbohydrates before, during, and after events, as necessary.
So, do these differences make one type of carbohydrate better than another? Depending on the context, yes.
- For well-being: complex carbohydrates should form the foundation of your lifestyle, thanks to their micronutrient and fiber content.
- For increasing training demand: simple carbohydrates may be the only realistic option to keep up with energy needs — this is exactly where sports drinks, gels, and even a banana with white bread pre-run make sense.
Understanding the differences and roles of carbohydrates is a valuable tool to move beyond the oversimplification of labelling one type as “good” and one as “bad”. Ultimately, the best strategy is the one that seamlessly fits your lifestyle — but also helps you keep up with your daily energy demands.
📚 This is article #7 in our macronutrient series. Explore the rest: Why we rely on carbs during exercise · Are carbohydrates the problem? · Animal vs plant-based protein · How much protein should we consume?
References
Fuchs, C. J., Gonzalez, J. T., Beelen, M., Cermak, N. M., Smith, F. E., Thelwall, P. E., Taylor, R., Trenell, M. I., Stevenson, E. J., & Van Loon, L. J. C. (2016). Sucrose ingestion after exhaustive exercise accelerates liver, but not muscle glycogen repletion compared with glucose ingestion in trained athletes. Journal of Applied Physiology, 120(11), 1328–1334. https://doi.org/10.1152/japplphysiol.01023.2015
Fuchs, C. J., Gonzalez, J. T., & Van Loon, L. J. C. (2019). Fructose co‐ingestion to increase carbohydrate availability in athletes. The Journal of Physiology, 597(14), 3549–3560. https://doi.org/10.1113/JP277116
Fuchs, C. J., Veeraiah, P., Hermans, W. J. H., Brauwers, B., Voncken, R., Brouwers, K., Petrick, H. L., Hendriks, F. K., Bels, J. L. M., Van Den Hurk, J., Weber, J., Senden, J. M., Smith, F. E., Thelwall, P. E., Prompers, J. J., & Van Loon, L. J. C. (2025). Carbohydrate intake of 10 g/kg body mass rapidly replenishes liver, but not muscle glycogen contents, during 12 h of post‐exercise recovery in well‐trained cyclists. The Journal of Physiology, JP289115. https://doi.org/10.1113/JP289115
Gonzalez, J. T., Fuchs, C. J., Betts, J. A., & Van Loon, L. J. C. (2017). Glucose plus fructose ingestion for post-exercise recovery — greater than the sum of its parts? Nutrients, 9(4), 344. https://doi.org/10.3390/nu9040344
Jeukendrup, A. E. (2010). Carbohydrate and exercise performance: the role of multiple transportable carbohydrates. Current Opinion in Clinical Nutrition and Metabolic Care, 13(4), 452–457. https://doi.org/10.1097/MCO.0b013e328339de9f
Jeukendrup, A. E., Redegeld, M., Martins, G., Whitfield, J., Burke, L. M., Mujika, I., Dolan, E., & Gonzalez, J. T. (2026). UCI Sports Nutrition Project: race nutrition for road cycling. International Journal of Sport Nutrition and Exercise Metabolism, 36(3), 215–232. https://doi.org/10.1123/ijsnem.2025-0239
Jeukendrup, A., & Gleeson, M. (2023). Sport nutrition (4th ed.). Human Kinetics.
Rebello, C. J., O’Neil, C. E., & Greenway, F. L. (2016). Dietary fiber and satiety: the effects of oats on satiety. Nutrition Reviews, 74(2), 131–147. https://doi.org/10.1093/nutrit/nuv063