The Science Behind Running Gel Sugars
Running gels are expertly engineered to provide a rapid and convenient source of carbohydrates to fuel your muscles during prolonged exercise. Unlike solid foods that require more extensive digestion, gels are formulated for quick absorption to prevent you from "hitting the wall" due to depleted glycogen stores. The key to their effectiveness lies in the specific types and ratios of sugars used.
Maltodextrin
Maltodextrin is arguably the most common carbohydrate in running gels and often appears first on the ingredient list. It is a complex carbohydrate, technically a polysaccharide, consisting of chains of glucose molecules. Because of this chain structure, it is digested and released into the bloodstream at a slightly slower rate than pure glucose, providing a more sustained release of energy and minimizing sharp blood sugar spikes and crashes. Maltodextrin is also less sweet than simple sugars, making it a good choice for products where a cloying taste might cause palate fatigue during a long race.
Fructose
Fructose, or "fruit sugar," is a simple sugar molecule found naturally in fruits and honey. Its primary value in running gels comes from its unique absorption pathway. While glucose and maltodextrin rely on the SGLT1 transporter in the gut, fructose uses a different transporter known as GLUT5. By combining these two types of carbohydrates, the body can utilize both pathways simultaneously, significantly increasing the rate at which it can absorb and oxidize carbohydrates. This dual-transport system allows for higher overall carbohydrate intake per hour, reducing the risk of gastrointestinal (GI) issues that can arise from relying on a single sugar source.
Glucose and Dextrose
Glucose is the body's preferred source of immediate energy. It is a simple sugar that is absorbed very quickly into the bloodstream. Dextrose is molecularly identical to glucose and is often used interchangeably in food production. Gels containing pure glucose or dextrose will provide a very fast, but often short-lived, spike in energy. They are most effective when combined with other carbohydrate sources like maltodextrin and fructose to create a more balanced and sustained energy profile.
Combining Sugars: The Dual-Carb Advantage
For endurance events lasting over 90 minutes, a single type of carbohydrate can limit absorption and potentially cause GI distress. This is because the SGLT1 transporter used for glucose can become saturated. By using a combination of glucose (via maltodextrin) and fructose, gels can leverage multiple absorption pathways to deliver more fuel to working muscles.
- Optimal Ratios: Research has investigated the best glucose-to-fructose ratio for maximizing absorption. While a 2:1 ratio was traditionally common, newer studies suggest that a 1:0.8 ratio may be even more effective for delivering higher carbohydrate loads (up to 120 g/h) with reduced GI symptoms. This is often utilized by newer hydrogel formulations, which also improve digestion.
- Other Ingredients: While sugars are the main component, gels often include other performance-enhancing ingredients:
- Electrolytes: Minerals like sodium and potassium are crucial for hydration and muscle function, as they are lost through sweat.
- Caffeine: A common addition to boost focus, increase alertness, and potentially reduce perceived effort during a run.
- Hydrogels: A newer technology that encases carbohydrates in a biopolymer matrix, allowing for a more concentrated solution that is easier on the stomach.
Comparing Carbohydrate Types in Running Gels
| Feature | Maltodextrin | Fructose | Glucose/Dextrose |
|---|---|---|---|
| Absorption Rate | Moderate/Slower | Quick | Very Quick |
| Energy Profile | Steady, Sustained | Quick Burst | Immediate Spike |
| Primary Function | Sustained energy, minimizes crashes | Complements glucose to maximize absorption | Immediate energy for working muscles |
| Sweetness Level | Low | High | Moderate |
| GI Impact | Gentle on the stomach due to low osmolality | Moderate (higher risk if overused without glucose) | Higher (can cause crashes if not balanced) |
| Transport Pathway | SGLT1 (after being broken down) | GLUT5 | SGLT1 |
Choosing the Right Gel for You
Selecting the best running gel is a personal process that requires experimentation during training runs. Considerations include the intensity and duration of your exercise, as well as your individual stomach sensitivity. Some runners thrive on a 2:1 glucose-fructose blend, while others find that newer hydrogel products or even natural alternatives like honey or maple syrup are better suited to their needs. It is critical to test your fuel strategy before race day to ensure you can tolerate your chosen gel without gastric distress. Always consume gels with water to aid absorption, unless it is an isotonic gel designed to be taken without water.
Conclusion
In summary, the sugar in running gels is not a single ingredient but a scientifically-formulated blend, typically including maltodextrin for sustained energy and fructose for enhanced absorption. Combining these carbohydrates leverages multiple transport pathways in the gut, allowing for a higher total energy intake per hour and helping to prevent GI issues and energy crashes. By understanding the function of each sugar, athletes can make informed decisions to optimize their fueling strategy and achieve their best performance. Remember to train with your chosen gel to find the right balance for your body.
Gu Energy Labs: Sugar and its Role in Endurance Sports
What are the carbohydrates in running gels?
Running gels contain a mix of carbohydrates, primarily maltodextrin (a complex carb) and simple sugars like fructose and glucose. This combination provides both quick and sustained energy release.
Do all running gels contain the same sugars?
No, different brands and formulas use varying combinations and ratios of carbohydrates. While most rely on maltodextrin and fructose, some use natural alternatives like honey or have specific ratios like 1:0.8 for enhanced absorption.
Why do gels use a mix of glucose and fructose?
The combination allows the body to use two different transport systems in the gut (SGLT1 for glucose and GLUT5 for fructose). This dual-pathway approach significantly increases the rate of carbohydrate absorption and reduces the risk of stomach issues.
Can I just use a regular sugary snack instead of a running gel?
While some sugary snacks can provide quick energy, they are not optimized for rapid absorption during exercise and may cause GI distress. Running gels are formulated for efficiency and ease of digestion.
How does the sugar in a running gel give me energy?
The carbohydrates in the gel are quickly absorbed into your bloodstream as glucose. This glucose is then transported to your muscles and organs to be used as fuel, providing a rapid energy boost.
What is the benefit of a hydrogel running gel?
Hydrogel technology, like that used by Maurten, encapsulates the carbohydrates in a biopolymer matrix. This allows for a higher concentration of carbs to be consumed without the typical GI discomfort associated with high sugar intake.
Why is it important to take water with a running gel?
For non-isotonic gels, water is essential to help with digestion and absorption. Consuming a concentrated gel without sufficient water can draw fluid into your stomach, potentially causing bloating or other GI problems.
