Carbohydrates in Sports Nutrition: What Every Athlete Needs to Know
By Seiji Ishii
Editor in Chief
Not all carbs are created equal. Here’s what you need to know about the different types fueling today’s elite athletes.
When you’re pushing through mile 18 of a marathon or grinding out the final hour of a century ride, your fuel choice can make or break your performance.
All carbohydrates provide energy, but the specific types found in sports drinks and gels work in distinctly different ways – and understanding these differences is crucial for endurance athletes.
The Carbohydrate Spectrum
Sports nutrition products primarily contain three categories of carbohydrates, each with unique absorption rates and performance benefits. The molecular structure of different carbohydrates determines how quickly they can be digested, absorbed and converted to usable energy.
Simple Carbs
Simple sugars form the foundation of most sports drinks and gels.
Glucose, the body’s preferred fuel source, appears in nearly every endurance product because it follows the fastest absorption pathway through the SGLT1 transporter in the small intestine.
Research shows that glucose can be oxidized at rates of up to 1.0-1.2 grams per minute¹, making it ideal for meeting immediate energy needs during high-intensity efforts.
Fructose takes a different route through the GLUT5 transporter. While absorbed more slowly than glucose, fructose serves a critical role in high-performance nutrition.
Studies demonstrate that combining glucose and fructose can increase total carbohydrate oxidation rates to 1.7-1.8 grams per minute – a 50% improvement over glucose alone².
Complex Carbs
Maltodextrin is super common in sports drinks and gels for good reason.
This complex carbohydrate is built from glucose molecules linked together in chains, typically ranging from 3 to 20 glucose units. Despite its complex structure, maltodextrin breaks down rapidly in the digestive system, providing a steady release of glucose without the spike associated with pure sugar.
The genius of maltodextrin lies in its osmolality. Because one maltodextrin molecule contains multiple glucose units, a drink can deliver more total carbohydrate with fewer individual particles, resulting in faster gastric emptying and reduced GI distress.
Research confirms that maltodextrin-based drinks empty from the stomach significantly faster than equivalent glucose drinks³.
Multiple Transporters: The Dual-Source Advantage
Discovering separate intestinal transporters for different sugars rocketed carbohydrate intake forward in one giant step.
Your small intestine contains distinct transporters: SGLT1 handles glucose and galactose, while GLUT5 specifically transports fructose. Combining carbohydrates that use different transporters effectively increases absorption capacity.
Research has demonstrated that athletes consuming glucose-fructose combinations during prolonged exercise exhibit improved performance compared to those consuming glucose only⁴.
Traditional formulations use a 2:1 glucose-to-fructose ratio, allowing carbohydrate absorption rates of up to 90 grams per hour, which surpasses the 60-gram-per-hour limit of glucose alone.
Beyond Traditional 2:1 Ratios
Recent research has challenged traditional 2:1 glucose-to-fructose ratios.
Studies show that other ratios, such as 1:0.8 maltodextrin-to-fructose formulations, can increase carbohydrate oxidation efficiency from 62% to 74%⁵. This adjustment allows athletes to achieve intake rates of 120 grams per hour – significantly higher than previously thought possible.
During controlled studies, athletes consuming these optimized formulations achieved peak oxidation rates of 1.58 g/min with 72% oxidation efficiency⁶, demonstrating dramatically improved fueling capacity.
Hydrogel Technology: Maurten’s Patented Innovation
Maurten’s patented hydrogel technology represents a fundamentally different approach from traditional gels and drinks.
This proprietary system creates a protective matrix that encapsulates carbohydrates for controlled release. When Maurten products reach the acidic environment of the stomach, natural polymers like sodium alginate and pectin form cross-linked networks that trap carbohydrates within a gel-like matrix.
This patented hydrogel structure transports carbohydrates through the stomach with minimal interaction, reducing the sensation of liquid sloshing and stomach distress associated with traditional drinks.
The hydrogel bypasses pooling in the stomach and delivers carbohydrates directly to the small intestine for absorption, allowing for higher intake rates with less GI distress.
Applications for Different Training Demands
Endurance Sports (2+ hours): Look for products with optimized maltodextrin-to-fructose ratios, such as 1:0.8 formulations. High-carbohydrate gels delivering 40+ grams of carbs per serving reduce feeding frequency while maintaining energy availability. Modern formulations allow for an hourly intake of 90-120 g to achieve sustained performance.
High-Intensity Events (30-90 minutes): Traditional 2:1 dual-source gels with 20-25 grams of carbohydrates are effective, as maximum absorption rates aren’t limiting factors. The immediate availability of glucose and maltodextrin matches your body’s urgent energy demands.
Ultra-Endurance (4+ hours): Advanced formulations with proven high intake rates become essential. Consider combining different product types – alternating between gels and drinks – to maintain an hourly intake of 90-120 grams while preventing flavor fatigue.
Optimizing Absorption and Minimizing Distress
The concentration of your carbohydrate drinks matters as much as the composition.
While traditional guidelines suggested 6-8% carbohydrate solutions for optimal gastric emptying, advanced formulations now enable higher concentrations – some products deliver 16% carbohydrate solutions through innovative delivery technologies (like Maurten Hydrogel).
Training your gut to handle race-day nutrition is essential. Regular consumption of your planned race nutrition during training sessions improves both tolerance and absorption⁷. Your intestinal transporters adapt to consistent carbohydrate exposure, allowing you to increase your carbohydrate intake rate over time.
Conclusions
The evolution from simple sugar water to scientifically formulated carbohydrate blends represents decades of research in exercise physiology. Modern sports nutrition leverages multiple carbohydrate types and absorption pathways to maximize energy delivery while minimizing digestive issues.
Whether you choose traditional dual-source formulations, cutting-edge hydrogel technology or optimized ratios, understanding how these different carbohydrate systems work helps you make decisions that can significantly impact your performance.
The key isn’t finding the “perfect” carbohydrate, but instead matching your fueling strategy to your event demands, personal tolerance and training adaptations. Test different combinations during training, pay attention to your body’s responses and remember that even the most advanced sports nutrition means nothing if you can’t execute the plan on race day.
References
Jeukendrup, A. E. (2004). Carbohydrate intake during exercise and performance. Nutrition, 20(7-8), 669-677. https://doi.org/10.1016/j.nut.2004.04.017
Wallis, G. A., & Wittekind, A. (2013). Is fructose a viable alternative to glucose in sports drinks? Sports Medicine, 43(11), 1181-1190. https://doi.org/10.1007/s40279-013-0084-x
Rehrer, N. J., et al. (1992). Gastric emptying, gastric secretion and enterogastrone response after administration of milk proteins or their peptide hydrolysates in humans. International Journal of Sport Nutrition, 2(1), 25-36. https://doi.org/10.1123/ijsn.2.1.25
Currell, K., & Jeukendrup, A. E. (2008). Superior endurance performance with ingestion of multiple transportable carbohydrates. Medicine & Science in Sports & Exercise, 40(2), 275-281. https://doi.org/10.1249/mss.0b013e31815adf19
O'Brien, W. J., et al. (2013). A carbohydrate ingestion strategy optimized for exogenous carbohydrate oxidation rates. Medicine & Science in Sports & Exercise, 45(9), 1814-1824. https://doi.org/10.1249/MSS.0b013e31828e11c4
Rowlands, D. S., et al. (2015). Composite versus single transportable carbohydrate solution enhances race and laboratory cycling performance. Applied Physiology, Nutrition, and Metabolism, 40(9), 865-872. https://doi.org/10.1139/apnm-2015-0067
Cox, G. R., et al. (2010). Effect of different protocols of caffeine intake on metabolism and endurance performance. Journal of Applied Physiology, 108(2), 275-283. https://doi.org/10.1152/japplphysiol.00972.2009