The Science Behind Energy Gels and Your Energy Stores
Energy gels are a concentrated source of carbohydrates, primarily simple sugars like maltodextrin and fructose, designed for rapid absorption. Their primary purpose is to replenish your body's glycogen stores, which are the main fuel source for your muscles during exercise. For runs shorter than 60-75 minutes, your body's existing glycogen is usually sufficient to sustain your effort. However, during prolonged exercise, such as a long training run or a marathon, these reserves begin to deplete. For many runners, this depletion starts around the 90-minute mark, leading to a sudden and significant drop in energy, commonly known as "hitting the wall". Strategic use of energy gels helps to delay this process, ensuring a continuous supply of fuel to your working muscles.
General Recommendations: How Often to Gel
For runs extending beyond 60-75 minutes, a consistent fueling strategy is necessary. The general recommendation is to start taking your first gel around the 45 to 60-minute mark of your run. This initial gel is preventative, topping up your energy before a significant drop occurs. Following the first gel, you should continue fueling at regular intervals. A good rule of thumb for most runners is to consume a gel every 30 to 45 minutes thereafter. This frequency helps maintain a steady energy supply without overwhelming your digestive system with too much sugar at once, which can lead to stomach upset. It's also important to consume gels with water (unless they are isotonic) to aid in digestion and absorption.
Customizing Your Gel Frequency
While general guidelines provide a good starting point, the ideal frequency is highly individual and depends on several factors.
- Body Size and Intensity: Runners with larger body weights or those running at a higher intensity will burn more calories and may need to consume more carbohydrates per hour, potentially requiring more frequent gels. For example, studies suggest ingesting 30-60g of carbs per hour for endurance activities, with elite athletes pushing for up to 90g. A typical gel contains 20-30g of carbs, so this could mean 2-3 gels per hour.
- Gut Tolerance: Your stomach's ability to process carbohydrates during exercise is trainable. Practicing your fueling strategy during long training runs is essential to see how your body reacts to different brands, textures, and quantities of gels. Never try a new gel or fueling approach on race day.
- Combining Fuel Sources: Gels do not have to be your only source of fuel. Some runners find success by combining gels with sports drinks or other fuel types, which might allow for less frequent gel consumption.
Creating a Race Day Fueling Plan
Race day nutrition begins long before the race starts with proper carbohydrate loading in the days prior to the event. On race day, execute the plan you practiced during your long training runs. For a half marathon, you might aim for 2-4 gels, spaced roughly 30-45 minutes apart after the first hour. For a marathon, the total number of gels can range from 4 to 8, depending on your pace and carbohydrate needs. A solid strategy involves mapping out when and where you'll take each gel in advance, factoring in race-specific elements like water stations.
Comparing Energy Gel Types
Not all gels are created equal. Different types cater to varying needs and preferences.
| Gel Type | Key Features | Water Requirement | Best For | Potential Drawbacks |
|---|---|---|---|---|
| Classic Gels | Concentrated carbs, often syrupy. | Yes, requires water for digestion. | High-intensity efforts and rapid fueling. | High concentration can cause GI issues if not taken with water. |
| Isotonic Gels | Pre-diluted with water, less concentrated. | No additional water needed for consumption. | Runners preferring a lighter consistency or who don't want to carry water. | Lower carb content per gel, so more might be needed. |
| Caffeinated Gels | Contains caffeine for a performance boost. | Varies by brand (check label). | Late stages of a long race for a mental lift or extra energy. | Can cause jitteriness or stomach upset if you are sensitive to caffeine. |
| Electrolyte Gels | Includes electrolytes to replace salts lost in sweat. | Varies by brand (check label). | Hot, humid conditions or for heavy sweaters. | May not replace all electrolytes; separate hydration is often necessary. |
Avoiding Common Gel Mistakes
- Waiting too long to fuel: Taking your first gel after you already feel tired is too late. The goal is to prevent the energy crash, not to recover from it.
- Overconsuming gels: Taking too many gels too quickly can cause stomach cramps, bloating, and nausea. Stick to the recommended dosage and listen to your body.
- Ignoring hydration: Consuming gels without enough water, especially traditional ones, can pull fluid from your bloodstream into your stomach to dilute the sugar, leading to dehydration.
- Trying a new brand on race day: Always test gels during training runs to ensure your stomach tolerates them and that you like the taste and texture.
- Forgetting to practice: Practicing with your planned race day nutrition is just as important as your physical training.
Alternative Fueling Options
For runners who dislike the texture or taste of gels, or who prefer a more varied approach, several alternatives can be used to achieve the same fueling goals.
- Sports Drinks: These provide both carbohydrates and electrolytes in liquid form, often easier for some to digest.
- Energy Chews or Gummies: Similar to gels, these offer a concentrated dose of carbohydrates in a solid, chewable form.
- Dried Fruit: Options like dates, raisins, and figs offer natural sugars and a source of quick energy. A small handful can be equivalent to a gel.
- Whole Foods: For longer, slower-paced events like ultra-marathons, some runners use bananas, boiled potatoes with salt, or homemade energy balls for a more substantial energy source.
For a deeper dive into the science of race nutrition, consider checking out resources from authoritative running publications, such as this guide from Runner's Need.
Conclusion
Knowing how often should you gel on a run is a personalized process that requires testing and adaptation. For runs over 60-75 minutes, a general rule is to start fueling after the first hour, then take a gel every 30-45 minutes to maintain steady energy levels. Factors such as your body size, running intensity, and gut tolerance all play a role in determining your optimal fueling schedule. The golden rule is to train as you race—test your fueling strategy during your long training runs to ensure a successful and cramp-free performance on race day. Whether you use gels, chews, or natural foods, consistent carbohydrate intake is the key to avoiding fatigue and finishing strong.
