Many athletes ask themselves how much sugar they should have, when, and from what sources.
Studies show eating or drinking carbohydrates before and during workouts improves performance in endurance exercise1. For decades sugars have been king of performance enhancement during exercise in endurance sports. Hundreds of companies make products with sucrose, glucose, maltose, dextrose and other forms of sugar. New research coming out now shows complex carbohydrates which digest slowly can be as beneficial for endurance sport performance when compared to fast digesting carbohydrates like sugars2. When compared to traditional sports drinks containing simple carbohydrates/sugars such as sucrose and maltose, these starches have been shown to promote higher rates of fat oxidation therefore improving performance3. By improving fat oxidation at higher intensities, the body spares glycogen to be used for the harder efforts required for racing. Some studies show that these forms of complex carbohydrates can cause nausea and other negative side effects which lower performance and negate the positive effects of fat oxidation2. Sugar is easily digestible (does not sit in the tummy for as long as other nutrients like protein and fat and complex carbohydrates) and converted into glucose as a quick fuel source for the muscles and brain during exercise. Sugar is found naturally in foods like fruit, grains, dairy, and starchy vegetables. It is also added to foods in forms such as table sugar, dextrose, maltodextrin, cane sugar, brown rice syrup, honey, coconut sugar, evaporated cane juice, and the list goes on. For this article we are talking about sugar as a nutrient, and are not distinguishing between sugar which is found naturally in foods and sugar added to foods. Regardless of where the sugar comes from, endurance athletes benefit from consuming it during exercise.
While we’re talking about sugars it is important to note that not all forms of sugar are created equal! The best forms of sugars to take in during workouts are glucose and sucrose. Fructose is the preferred fuel source for the liver and therefore is transported to the liver before being transported to the muscles. This makes fructose a slower acting sugar during exercise when compared with glucose which goes straight to the muscles and brain. It is also best to take in a variety of forms of sugar. Each type of sugar has a specific receptor in the body used to take it in as fuel (fructose has a fructose receptor, glucose has a glucose receptor). It is best to take in food and drink with a mix of sucrose and glucose.
Not all foods and products work the same for every individual. It is important for every athlete to find sports drinks, foods, and sports food products which do not cause tummy distress. Even if the product appears to have a great formula, it may not work for each athlete who tries it. Athletes can be their own case study.
Try a few different products out containing various types and forms of carbohydrate (read ingredient lists) during similar workouts and take notes on how you feel.
Try these foods which have a mix of types of carbohydrates for workouts and racing: figs, dates, potatoes, rice balls, gels, chomps, blocks, chews.
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About the author: Kristen Arnold MS, RDN, CSSD is a level 2 USA Cycling coach as well as a Registered Dietitian (RD) specializing in sports nutrition and is a board Certified Specialist in Sports Dietetics (CSSD). With Kristen’s nutrition expertise and diverse experience in the sport of cycling as a racer and a mentor, she provides a comprehensive approach to her coaching. She works with athletes from the beginner to elite ranks in road, cyclocross, and mountain biking disciplines. Kristen is also a category 1 domestic elite road racer and seasoned mountain bike and cyclocross racer. Learn more about Kristen.
- Smith, J. W., D. D. Pascoe, D. H. Passe, B. C. Ruby, L. K. Stewart, L. B. Baker, and J. J. Zachwieja. “Curvilinear Dose-Response Relationship of Carbohydrate (0-120 g. h-1) and Performance.” Medicine and Science in Sports and Exercise 45, no. 2 (2013): 336-41.
- Baur, D., Vargas, F., Bach, C., Garvey, J., & Ormsbee, M. (2016). Slow-Absorbing Modified Starch before and during Prolonged Cycling Increases Fat Oxidation and Gastrointestinal Distress without Changing Performance. Nutrients,8(7), 392. doi:10.3390/nu8070392
- König, D., Zdzieblik, D., Holz, A., Theis, S., & Gollhofer, A. (2016). Substrate Utilization and Cycling Performance Following Palatinose™ Ingestion: A Randomized, Double-Blind, Controlled Trial. Nutrients,8(7), 390. doi:10.3390/nu8070390
- Maresch, C. C., Petry, S. F., Theis, S., Bosy-Westphal, A., & Linn, T. (2017). Low Glycemic Index Prototype Isomaltulose—Update of Clinical Trials. Nutrients,9(4), 381. doi:10.3390/nu9040381