Your Ultimate Guide to Running Gels

Your Ultimate Guide to Running Gels

Fueling during your run with carbohydrates helps you run for longer without fatigue. One of the simplest options for fueling during a run is running gels. Running gels contain easily digestible carbohydrates and do not require chewing. 

Gels are popular for a reason – they work. However, not every runner likes taking gels. This article delves into the science of running gels, how to pick the right gel for you, how often to take them, and alternative options for fueling on a run.  

The Science of Why Running Gels Help Performance

When you run for longer than 80-90 minutes, you begin to burn through your muscle glycogen stores. If you were to just keep running without eating anything, you would eventually slow down. When your body begins to deplete glycogen, it switches to primarily fat oxidation as a protective mechanism. (Complete glycogen depletion has dangerous consequences.) Fat oxidation can sustain you for a long period of time; however, it only is dominant at intensities below 60% VO2max (slower than easy pace for most recreational runners). As a result, you have to slow down significantly. 

Glycogen depletion occurs more quickly at higher intensities (marathon pace or above). However, intensity is not the only factor. At an easy run pace, you will still begin to deplete glycogen stores after 90-ish minutes. 

Fueling during long runs over 90 minutes or hard workouts over 60-70 minutes spares muscle glycogen. Carbohydrates such as running gels provide easily available energy. When you eat the gels, they are broken down into glucose in your blood, which your body can then rapidly transport to the working muscles for energy production. Those carbohydrates help you run faster and for longer with less fatigue. 

Taking running gels may also be protective against muscle breakdown. If you do not have adequate carbohydrates available, your body utilizes protein from your muscles for energy. This process is called gluconeogenesis (turning protein into glucose) and can account for up to 10% of energy production on prolonged efforts. However, muscle breakdown comes with a cost: recovery time and injury risk both increase. Consuming carbohydrates such as running gels during a long run has a protein-sparing effect, meaning that you have less muscle breakdown. 

There are many options for fueling on your runs: sports drinks, whole foods, energy chews, and running gels. Running gels provide an easy-to-ingest form of semi-solid carbohydrates that are formulated for easy digestion and rapid energy. 

What to Look for in a Running Gel

  • Multiple transportable carbohydrates: As described in a seminal 2014 review in Sports Medicine, a combination of glucose and fructose has a higher oxidation rate than glucose alone (1.26 g/min vs 1 g/min). Your body has multiple transporters for different types of carbohydrates. Glucose uses a sodium-dependent transporter (SGLT1). Fructose uses GLUT5. As a result of using different transporters, your body can absorb more of the carbohydrates for energy. Additionally, multiple transportable carbohydrates may reduce the risk of GI distress. This is likely due to not overloading a single transporter. Many gels are formulated with both glucose and fructose.  
  • Little to no protein: Some evidence exists that small amounts of protein may reduce muscle breakdown during endurance exercise. Some gels do contain small amounts of protein (often BCAAs) to mitigate muscle damage. However, protein is slower to digest and has a higher thermic effect (it takes more energy to digest). Slower digestion can lead to GI issues while running, so it is best to avoid sizable amounts of protein.   
  • Minimal to no fat: Similar to protein, fat delays gastric emptying rate. This is great when you want to be satisfied after a meal, but not ideal when you are running. Too much fat can increase the likelihood of GI distress during runs. 
  • Tolerable flavor: Everyone has different palatable preferences. Do you like sweet, savory, or relatively bland? Ultimately, you should like (or at least tolerate) how your gel tastes. If you don’t like the flavor of Maurten, it’s not worth it even if everyone raves about it. 

How Often Should I Take Running Gels?

Most running gels contain 20-25 grams of carbohydrates per serving. (Some contain more or less, so always check the label). A recommended goal is 30-40 grams per hour for runs lasting 1-2 hours, 40-60 grams per hour for runs lasting 2-3 hours, and 60-90 grams per hour for runs lasting more than 3 hours. 

  • 1-2 hours: a gel every 40-45 min
  • 2-3 hours: a gel every 30-40 min
  • 3+ hours: a gel every 20-30 min

You do not need to take the entire gel in one bite. You can sip at it over a few minutes and take time to breath in between gulps.

If you are running for less than 70-90 minutes (depending on intensity), you do not need to take a gel on your run. On runs less than 70-90 minutes, your body can produce energy without exogenous sources – and doing so improves your fat oxidation and glycogen sparing without risk. Ensure you eat enough before (here’s what to eat before a run) a run of any length.

Should I Use Caffeinated Gels? 

Caffeine can improve endurance performance by up to 2-4%, according to the International Society of Sports Nutrition position stand. Caffeine during exercise can reduce perceived exertion and improve pain tolerance. Due to its ergogenic effect, some running gels contain caffeine in doses of 50-100 mg per serving. 

However, caffeine can cause gastrointestinal distress, especially during exercise. Changes in blood flow during exercise can affect caffeine absorption. You should always test caffeinated gels in training, first on medium-long runs (rather than your big 20-mile run, for example). Once you establish tolerance, you then want to also test the caffeinated gel during higher intensity efforts at race pace. 

If you do take caffeinated gels, do not take every gel as caffeinated. I typically recommend to my athletes to only have one to two caffeinated gels in a marathon to stay within the recommended dose of 3-6 mg/kg. 

What if Running Gels Hurt My Stomach?

Every runner has an individual response to different sports nutrition products. You may find that a certain brand of gel upsets your stomach. That does not mean that all gels are bad. Rather, it means it can take some trial and error to find the running gel that works best for you. 

Gels can upset your stomach if:

  • They are not taken according to directions. Some gels require 4-6 oz of fluid for digestion. Other gels do not require fluid. Always check the package for instructions and take it with fluid if appropriate. 
  • You did not gut train. As described in a 2011 review in Sports Medicine, you can reduce the likelihood of GI upset on race day. The GI system is adaptable; by gradually introducing and increasing carb intake on runs, you can train your body to digest gels in larger amounts. You need to allow several weeks for this adaptation to occur. Practice your fueling strategy repeatedly in training (and build up to it first) rather than waiting until race day. 
  • You are dehydrated. Dehydration increases the chance of GI upset on runs. Ensure that you are well hydrated before exercise and be diligent about replacing fluids during exercise. 
  • You need a different formulation. In some scenarios, high amounts of fructose can be irritating to the gastrointestinal system. Many gels are formulated to have small amounts of fructose, but individual tolerances may differ. If a gel irritates your stomach, try a different brand and see how you respond. 
  • You wait too long to start fueling. When you run, your body shunts blood flow from the gastrointestinal system to the working muscles. If you start fueling earlier in the run (first gel within 30-40 minutes), you can maintain some blood flow for better gastric emptying rates. 

The Best Running Gels

Maurten:
  • Flavor: unflavored sweet (some say it tastes like marshmallow or agave nectar)
  • Texture: Hydrogel (thicker, jelly-like consistency)
  • 25 g carbohydrate (1:0.8 glucose:fructose ratio)
  • 85 mg sodium 
  • Hydrogel may be easier to digest
  • Uncaffeinated or 100 mg caffeine
  • Does NOT require water to digest
Science in Sport (SIS): 
  • Flavors: Fruit flavors and espresso (caffeine)
  • Texture: Thin, almost liquid-like
  • 22 g carbohydrate (main ingredient: maltodextrin)
  • 10 mg sodium 
  • Isotonic solution may be easier to digest
  • Uncaffeinated or 75 mg caffeine
  • Does NOT require water to digest
GU:
  • Flavors: Unflavored, fruit flavor, sweet (chocolate, cake), espresso, etc. 
  • Texture: Typical semi-solid texture of gels
  • 22 g carbohydrate (maltodextrin and fructose)
  • 60 mg sodium 
  • Has branched-chain amino acids (BCAAs)
  • Uncaffeinated or 40 mg caffeine
  • Does require water to digest
Spring Energy:
  • Flavors: Fruit flavored and nut flavored (Speednut and Koffee have higher amounts of fat and are best for ultramarathons)
  • Texture: Fruit puree
  • 17-45 g carbohydrate (rice and fruits) (each flavor has different amounts so check the label)
  • 30-85 mg sodium 
  • Uncaffeinated or 10-15 mg caffeine
  • Does require water to digest
Huma:
  • Flavors: Fruit or chocolate
  • Texture: Typical semi-solid texture of gels
  • 22 g carbohydrate (2:1 glucose: fructose)
  • 105 mg sodium 
  • Chia seeds may be gut irritants for some people (1 g fiber per seving)
  • Uncaffeinated or caffeinated
  • Does require water to digest

Alternatives to Running Gels

While running gels are effective and practical, they are not the only option. If you do not like gels, other alternatives for carbohydrate intake on runs include sports drinks, energy chews, and even whole foods! Experiment and find what works for you. This article delves more into alternative options for fueling!

For more on fueling:

How to Fuel during a Half Marathon
How to Fuel during a Marathon
What to Eat Before a Race
Do You Need Electrolytes?

Disclaimer: I have an MS in Applied Exercise Science – Sports Nutrition. However, this is generalized advice.

References not cited above:

Jeunkendrup, A. & Gleeson, M. (2016). Sport nutrition. 3rd ed. Human Kinetics.

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3 Responses

  1. I recently listened to a podcast (run to the top) and he had a guest selling his product which was amino acids. He recommended taking them before early morning runs if you don’t like to eat before (that is me) and also after to help with muscle recovery. What are your thoughts. I really like Honey stinger both gu and chews. I usually rotate those on my long runs plus I carry a handheld with Nuun Endurance. Thanks for your articles!!

    1. Hi Carol,

      Thank you for commenting! Amino acid supplementation does not replace pre-run carbohydrates; your body does not use amino acids in the same way as carbs. That said, small amounts of protein combined with carb before a run can be beneficial. Branched-chain amino acids may be beneficial during a run, such as you see in GU products. However, after a run, it’s best to use a complete protein (food or protein powder) with a complete amino acid profile, rather than just using an amino acid supplement. I hope this helps!

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