1:1 Glucose–Fructose Ratio: The Gold Standard for Endurance and Gut Comfort
The Speed Read: 1:1 Glucose–Fructose Maximises Performance and Gut Comfort
Imagine pushing through the final miles of an endurance event—your energy is steady, your gut feels calm, and you’re performing at your best. That’s the power of the right fuelling strategy using truefuels. A 1:1 glucose-to-fructose ratio is a key component of our Performance Gels. By tapping into both of the body’s carbohydrate transport systems, this balanced approach delivers rapid, sustained energy while minimising the risk of GI distress, helping you go further, faster, and more comfortably.
Starting point
For professional athletes like me to hobby athletes, carbohydrate strategy is a cornerstone of performance. The debate around the optimal glucose: fructose ratio is more than academic—it directly impacts energy availability and gut comfort during training and competition. At truefuels, we combine scientific rigour, athlete feedback, and the latest research to deliver a gel formulated with a 1:1 glucose: fructose ratio. Here’s why this ratio stands out as the gold standard.
The Science of Carbohydrate Absorption and Oxidation
- Glucose uses the sodium-glucose co-transporter (SGLT1).
- Fructose uses the GLUT5 transporter.
- Co-ingestion enables both transporters to work in parallel, increasing total carbohydrate uptake and oxidation.
Key Evidence:
- Glucose alone: ~1 g/min oxidation.
- Glucose + fructose (1:1): up to 1.75 g/min oxidation.
- Oxidative efficiency (oxidised/ingested): ~73% at high ingestion rates.
High oxidative efficiency is crucial for minimising GI symptoms and maximising usable energy during long efforts.
Figure 1: Carbohydrate oxidation efficiency peaks at 1:1 fructose-to-glucose ratio during endurance exercise. (adapted from O’Brien et al. 2013)
What Is the Optimal Glucose:Fructose Ratio?
Research consistently points to an optimal range of 1:0.7 to 1:1.1 for glucose:fructose:
| Ratio | Oxidation Rate (g/min) | GI Distress | Performance Impact |
|---|---|---|---|
| 2:1 | Lower | Higher | Less optimal |
| 1:0.8–1:1 | Highest (~1.75) | Lowest | Best endurance outcomes |
| 0.5:1 or 1.25:1 | Lower | Variable | Less optimal |
- Rowlands et al. (2015): Highest oxidation at 1:0.7–1:1.1.
- Jentjens & Jeukendrup (2005): 1:1 ratio outperforms glucose or maltodextrin alone.
- O’Brien et al. (2013): Oxidation efficiency peaks near 1:1.
Gut Comfort: The 1:1 Ratio Advantage
GI distress—cramping, bloating, nausea—can derail performance. The 1:1 ratio:
- Reduces osmotic pressure in the gut, speeding fluid absorption.
- Distributes carbohydrate load across two transporters, minimising transporter saturation.
Supporting Studies:
- O’Brien et al. (2011): 1:0.8 ratio had the lowest GI distress during high-intensity cycling.
- Podlogar & Wallis (2020): Mixed carbohydrate sources improve oxidation and gut comfort, even when ratios are slightly off 1:1.
Endurance Performance: Sustained Energy, Measurable Gains
- Higher carbohydrate oxidation rates enable athletes to maintain intensity over longer periods.
- Rowlands et al. (2015): 1–9% improvement in mean power output with glucose–fructose beverages vs. glucose alone.
- O’Brien et al. (2013): 0.8:1 ratio improved exogenous carbohydrate oxidation compared to less balanced ratios.
Real-world trend: Endurance athletes are pushing higher carbohydrate ingestion rates, but the literature supports a ceiling of ~1.75 g/min for safe and effective oxidation.
Why Not 2:1? The Evidence for 1:1
While some products use a 2:1 glucose:fructose ratio, the latest research suggests this can saturate SGLT1 and limit total oxidation, increasing the risk of GI distress. The 1:1 ratio:
- Engages both SGLT1 and GLUT5 transporters fully.
- Maximises oxidation efficiency and energy delivery.
- Minimises GI symptoms, supporting performance in real-world conditions.
Practical Takeaways
How to Put the 1:1 Ratio into Practice
- Choose products with a 1:1 glucose-to-fructose ratio for sessions or races lasting more than 90 minutes.
- Test your fuelling plan during training—everyone’s gut is unique, so find your sweet spot before race day.
- Start with 60–90g of carbohydrate per hour and adjust based on comfort and performance.
- Track your GI symptoms and energy levels in a training log to fine-tune your intake.
- Stay consistent: Use the same products and strategies in both training and competition to build confidence and reliability.
Conclusion
While the science is clear, what sets truefuels apart is our commitment to real-world testing with athletes of all levels—from weekend warriors to elite competitors. Our Performance Gel is not just formulated in the lab; it’s refined on the road, on the trail, and in competition. I put in my 20 years of experience. We use only the highest-quality ingredients, with no unnecessary additives, ensuring you get pure, reliable energy when it matters most. Trust in a product that puts both science and athlete experience at the forefront of every batch.
References
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Jeukendrup AE. (2010). Carbohydrate and exercise performance: the role of multiple transportable carbohydrates. Current Opinion in Clinical Nutrition & Metabolic Care, 13(4), 452–457.
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Rowlands DS, Houltham S, Musa-Veloso K, et al. (2015). Fructose–Glucose Composite Carbohydrates and Endurance Performance: Critical Review and Future Perspectives. Sports Medicine, 45, 1561–1576.
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Rowlands DS, Thorburn MS, Thorp RM, et al. (2007). Effect of graded fructose coingestion with maltodextrin on exogenous 14C-fructose and 13C-glucose oxidation efficiency and high-intensity cycling performance. Journal of Applied Physiology, 104(6), 1709–1719.
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O’Brien WJ, Rowlands DS. (2011). 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, 300(2), G181–G189.
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Podlogar T, Wallis GA. (2020). Impact of Post-Exercise Fructose-Maltodextrin Ingestion on Subsequent Endurance Performance. Frontiers in Nutrition, 7, 82.
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O’Brien WJ, Stannard SR, Clarke JA, Rowlands DS. (2013). Fructose–Maltodextrin Ratio Governs Exogenous and Other CHO Oxidation and Performance. Medicine & Science in Sports & Exercise, 45(9), 1814–1824.
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Jentjens RL, Jeukendrup AE. (2005). High rates of exogenous carbohydrate oxidation from a mixture of glucose and fructose ingested during prolonged cycling exercise. British Journal of Nutrition, 93(4), 485–492.
About the Author
Alistair Brownlee is a two-time Olympic gold medallist, Ironman Champion, and co-founder of Truefuels. He is driven by a belief in science-backed training, clear structure, and removing friction from performance.