~ Annie Bothma, Elite Athlete, IOPN Performance Sports Nutritionist (EQF Level 7. Masters), Running & Strength Coach
Effective fueling is crucial for endurance athletes to maintain performance and stave off fatigue during long training sessions and races. With a wide array of sports gels available, how do you choose the right one for your needs?
This guide will walk you through the science of sports gels, focusing on the role of multiple transportable carbohydrates and the optimal glucose-to-fructose ratio. Additionally, l will provide practical tips to help you choose the best gel for your race-day nutrition plan.
Understanding Carbohydrate Intake Guidelines
To optimize your fueling strategy, it’s essential to consider both the duration of your exercise and your carbohydrate needs. Here’s a breakdown based on the latest sports science:
Up to 1 Hour
30g of carbohydrates per hour is sufficient, with any glucose-to-fructose ratio being effective.
1 to 2 Hours
Increase your intake to 60g per hour. A 2:1 glucose-to-fructose ratio maximizes absorption without overwhelming your gut.
2 to 3 Hours
Consider increasing to 90g per hour. The glucose-to-fructose ratio becomes even more critical, with a range of 2:1 to 0.8:1 depending on your tolerance.
3+ Hours (Ultra-Endurance Events)
Push your intake to 120g per hour if performance is a priority. At these levels, precise ratios and personal tolerance are crucial to avoid gastrointestinal distress while maximizing energy supply.
Exercise Duration | Total Carb Intake per Hour | Glucose Intake | Fructose Intake | Glucose to Fructose Ratio |
Up to 1 hour | 30g/h | Included in total | Included in total | Most ratios work well |
1 to 2 hours | 60g/h | 40g/h | 20g/h | 2:1 |
2 to 3 hours | 90g/h | 60g/h | 30g/h | 1:1 |
More than 3 hours | 120g/h | 65g/h | 55g/h | 0.8:1 |
The Science Behind Multiple Transportable Carbohydrates
During prolonged exercise, your body’s ability to absorb and utilize carbohydrates is key to sustaining energy levels. Research shows that combining different types of carbohydrates—particularly glucose and fructose—can significantly enhance absorption and oxidation rates. These carbohydrates use different transporters in the intestine, reducing the risk of saturation and allowing for greater carbohydrate uptake.
Optimal Glucose-to-Fructose Ratio
The 2:1 glucose-to-fructose ratio is considered ideal for maximizing carbohydrate absorption and utilization during endurance activities. This specific ratio enables athletes to absorb up to 90g of carbohydrates per hour, significantly higher than the 60g per hour when relying on glucose alone. The dual absorption pathways reduce the risk of transporter saturation, allowing for higher rates of carbohydrate oxidation—up to 1.3g per minute. Moreover, this balanced ratio can help minimize gastrointestinal issues, a common concern when consuming large amounts of carbohydrates during intense exercise.
Four Practical Tips for Choosing the Right Gel
Selecting the right gel involves more than just choosing your favorite flavor. Here’s what to consider:
1. Carbohydrate Content
Choose a gel that contains multiple transportable carbohydrates if you are ingesting more than 60g of carbohydrates per hour. Ensuring your gel contains both glucose and fructose, ideally in a 2:1 ratio or a 1:08 ratio if you are using higher carbohydrate intakes is key.
2. Texture & Taste
Gels come in a variety of flavors and consistencies, so it may take some trial and error to find your perfect match. It is crucial to practice taking in gels during training. This will not only help you get used to the taste and texture but also allow your body to adapt to digesting it during physical activity.
Remember to hydrate adequately, as gels are often most effective when taken with water. Hydrogels can be taken without water, but you still need to make sure you meet your overall hydration needs during exercise.
Choose a gel you enjoy—if you like the taste, you’re more likely to use it when you need it most.
3. Cost
Take into account your budget, particularly if you plan on using gels often for extended and intense training sessions. It's essential to ensure that your stomach can handle these products during high-intensity workouts or prolonged exercise sessions.
4. Nutritional Composition
Check for additional ingredients like electrolytes or caffeine, which might be beneficial depending on your needs. On the flip side if you are sensitive to caffeine and it is not something you use habitually in your diet it may cause gastrointestinal upset or make you feel jittery. Therefore, make sure you read the label carefully before buying a product.
Common Questions About Sports Nutrition Gels
What makes a gel isotonic?
An isotonic gel contains a balance of carbohydrates and electrolytes that match the osmotic pressure of body fluids, allowing it to be absorbed quickly without needing extra water.
Should you consume gels all at once?
This depends on your personal tolerance and exercise intensity. Some athletes prefer consuming gels gradually to avoid overwhelming the stomach and reducing the risk of gastrointestinal distress.
Why do some athletes experience stomach issues with gels?
Stomach issues can arise due to the type of carbohydrate or the concentration of the gel. Consuming gels with insufficient water or using gels that contain difficult-to-digest sugars like fructose can lead to discomfort.
How much gel should you use during an endurance event?
For events lasting 1-2 hours, 60g of carbohydrates per hour is generally recommended. For longer events, consider increasing your intake to 90-120g per hour.
What are the best alternatives to gels for fueling?
Alternatives include sports drinks, energy chews or blocks, and real food options like bananas, dried fruit, or energy bars. The best choice depends on your personal preference and how well you tolerate the fuel source.
How can you effectively increase your carbohydrate intake during exercise?
Gradually train your gut by increasing the amount of carbohydrate consumed during training sessions. Experiment with different carbohydrate sources and practice at race intensity to ensure your body can handle the intake.
Key Questions to Ask Yourself When Choosing Your Fuel Source
Professor Asker Jeukendrup at MySportScience, came up with three great questions to ask yourself before a finalizing your race-day nutrition plan:
How long is your exercise session?
Is performance a top priority?
Will you be expending more than 500 kcal per hour on average?
If you answer “yes” to questions 2 and 3, use the chart provided earlier to determine your carbohydrate needs. If performance is less of a priority or your caloric expenditure is lower, you might adjust your intake slightly.
Below are a few of the top gel brands, along with their carbohydrate levels, and key points to keep in mind when selecting the most suitable gel for your needs.
Brand | Gel Name | Category | Carbohydrates (g) | Sodium (mg) | Notes |
GU | GU Energy Gel | Multiple Transportable Carbs | 22 | 60 | Contains both maltodextrin and fructose (2:1 ratio) |
SiS | SiS GO Isotonic Energy Gel | Isotonic Gel | 22 | 10 | No need for additional water, low sodium |
Maurten | Maurten Gel 100 | Hydrogel | 25 | 36 | Hydrogel technology for smooth digestion |
Clif | Clif Shot Energy Gel | Single Carbohydrate (Maltodextrin) | 24 | 90 | High sodium content |
Honey Stinger | Honey Stinger Organic Gel | Single Carbohydrate (Honey) | 24 | 50 | Made from organic honey, no fructose |
PowerBar | PowerGel Hydro | Multiple Transportable Carbs | 27 | 200 | Contains maltodextrin and fructose (2:1 ratio), high sodium |
Huma | Huma Chia Energy Gel | Multiple Transportable Carbs | 21 | 100 | Good Multiple Transportable Carbs option |
Tailwind | Tailwind Rebuild Gel | Multiple Transportable Carbs | 25 | 110 | Good Multiple Transportable Carbs option |
GU | GU Roctane Ultra Endurance | Multiple Transportable Carbs | 23 | 125 | Contains amino acids, higher sodium for ultra events |
Maurten | Maurten Gel 160 | Hydrogel | 40 | 84 | Higher carb content, uses hydrogel technology |
SiS | SiS Beta Fuel Gel | Multiple Transportable Carbs | 40 | 40 | 1:0.8 ratio of maltodextrin to fructose, optimized for endurance |
Precision Hydration | Precision Hydration Gel | Electrolyte + Carbs | 30 | 500 | High sodium, designed for hot/humid conditions |
Conclusion
Not all gels are created equal. Understanding the science behind carbohydrate absorption and using this knowledge to inform your fueling strategy can make a significant difference in your performance. The 2:1 glucose-to-fructose ratio has proven to be highly effective for endurance athletes, offering greater carbohydrate absorption, reduced reliance on glycogen stores, and overall better performance. Use the guidelines and tips provided to optimize your fueling strategy and get the most out of your training and races.
If you’re unsure about how to fuel your training sessions properly or need personalized advice, I’m here to help. Let’s work together to tailor your nutrition and maximize your performance and health.
Contact me at anniesathletes@gmail.com for more information.
Follow @annies_athletes on Instagram for more content like this.
Resources
Gonzalez, J. A., Braun, B., Dennis, M. E., et al. (2015). Increased exogenous but unaltered endogenous carbohydrate oxidation with combined fructose‐maltodextrin ingested at 120 g/h versus 90 g/h at different ratios. Scandinavian Journal of Medicine & Science in Sports, 10.1111/sms.12618.
Jeukendrup, A. E., & Meeusen, R. (2010). Superior Endurance Performance with Ingestion of Multiple Transportable Carbohydrates. Medicine & Science in Sports & Exercise, 10.1249/MSS.0b013e3181dc2f8a.
Jeukendrup, A. E., & Meeusen, R. (2004). Oxidation of combined ingestion of glucose and fructose during exercise. Journal of Applied Physiology, 10.1152/japplphysiol.00762.2003.
Vergauwen, S., Hespel, M., et al. (2020). Glucose and Fructose Hydrogel Enhances Running Performance. Journal of the International Society of Sports Nutrition, 10.1186/s12970-020-00380-x.
Asker Jeukendrup, Micheal Gleeson, Sport Nutrition, Third Edition, 2019
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