As both a runner and a coach, I know how critical a well-dialed fueling plan is—especially in long-distance races like the marathon. Fitness gets you to the start line, but fueling determines how strong you finish.
One of the most practical and effective tools for maintaining energy and avoiding the wall is the strategic use of energy gels. These compact packets deliver a concentrated source of carbohydrates that help preserve muscle glycogen and maintain blood glucose levels as the miles stack up.
And fueling practices have evolved significantly in recent years. While runners once aimed for 30–40 grams of carbohydrate per hour (about one gel per hour), many competitive marathoners today are targeting 60–90 grams of carbs per hour (2–3 gels).
I’ll walk you through everything you need to know about running with gels, including what they are, how they work physiologically, when to take them, how much you may need, how to train your gut to tolerate them, and how to determine whether they fit into your overall fueling strategy.
The goal isn’t just to survive the race, but to fuel in a way that allows you to perform at your full potential from start to finish.
What Are Energy Gels Exactly?
Energy gels are one of the most widely used fueling tools for endurance athletes. They provide a quick source of carbohydrates—usually around 100 calories or 20–25 grams per gel—to help maintain energy levels, preserve glycogen stores, and delay fatigue during long efforts.
Most gels contain a blend of simple sugars like glucose and fructose, though some use maltodextrin, a less sweet, easily digestible carbohydrate that can be easier on the stomach for some runners.
Formulations vary by brand, and ingredients like electrolytes (sodium, potassium, magnesium) and caffeine are often included to support hydration and focus.
Runners who are sensitive to fructose should look for gels made primarily with glucose or maltodextrin to reduce the risk of GI issues. Likewise, if you find gels overly sweet or thick, options with a higher maltodextrin ratio tend to have a more neutral taste and a smoother texture.
Caffeine can enhance endurance and alertness, but it may also cause digestive distress or an increased heart rate in some individuals, so it’s important to test caffeinated gels in training first.
Ultimately, the best energy gel for you will depend on your personal taste preferences, digestive tolerance, and fueling needs. Always try different brands, flavors, and timing strategies during long runs to find what works best—never experiment for the first time on race day.
Why Running With Gels Works
Because the carbs in energy gels are simple sugars, very little digestion is required before the sugars can enter your bloodstream as usable glucose.
This means that you get usable energy quickly, and the digestive system does not need to work hard to break down complex carbohydrates, proteins, fat, or fiber, which take quite a bit of time and are relatively incompatible with high-intensity exercise.
This is because when you are running or performing the high-intensity exercise, blood flow increases to the heart and muscles, and to compensate for the higher oxygen and nutrient needs of these tissues; blood flow decreases to the digestive tract.
This is why it is difficult to digest food while running, and consuming too many carbohydrates, a heavy meal, fatty foods, or excessive fiber or amino acids before or during exercise can cause cramping, bloating, diarrhea, gas, nausea, and vomiting.
Energy gels, chews, sports jelly beans, Gu chomps, and sports drinks are running nutrition products specifically formulated with only simple sugars, so digestion is minimal, and the fuel provides a quick energy source to keep your energy levels stable during longer runs or races.
Note that energy gels aren’t necessarily “healthy” for your everyday running nutrition plan. They are highly processed, but this type of running fuel has its place in your training and racing.
There are also more natural energy gels like Huma Chia Energy Gels. Studies have demonstrated1Lestari, Y. N., Farida, E., Amin, N., Afridah, W., Fitriyah, F. K., & Sunanto, S. (2021). Chia Seeds (Salvia hispanica L.): Can They Be Used as Ingredients in Making Sports Energy Gel? Gels, 7(4), 267. https://doi.org/10.3390/gels7040267 that chia seed gels can provide equally effective performance benefits to standard processed energy gels.
How Many Gels Should You Take Per Hour?
Using energy gels is generally unnecessary for runs under 60 minutes, especially if you’re well-fueled beforehand. Your stored glycogen is typically sufficient to support efforts of that duration, even at moderate to high intensity.
Once workouts or races move beyond the 75–90-minute mark, fueling becomes increasingly important to maintain performance. At that point, you’re no longer just “topping off,” you’re actively working to preserve glycogen stores and prevent the sharp drop in energy commonly known as bonking.
Traditional guidelines from the American College of Sports Medicine (ACSM) suggested 30–60 grams of carbohydrate per hour for endurance efforts lasting 1–3 hours.2American College of Sports Medicine. (2009). Nutrition and Athletic Performance. Medicine & Science in Sports & Exercise, 41(3), 709–731. https://doi.org/10.1249/mss.0b013e31890eb86 That range still applies for many recreational athletes. However, modern sports nutrition research, particularly in elite marathon and cycling populations, has shown that higher intakes can improve performance when tolerated.
It is now common to see athletes consuming anywhere from 30 to 120 grams of carbohydrate per hour, depending on duration, intensity, and gut training.
Here’s how that breaks down in practice:
- 30–45 g/hr: Appropriate for shorter endurance events (~90 minutes), lower intensities, or athletes new to fueling.
- 60 g/hr: A strong evidence-based baseline for most marathoners.
- 75–90 g/hr: Increasingly common in competitive marathoners and half-marathoners running at high intensity.
- 90–120 g/hr: Primarily seen in elite athletes or very long events, using multiple carbohydrate sources (e.g., glucose + fructose blends) and after specific gut training.
Why the range?
The limiting factor isn’t just what your muscles can use; it’s what your gut can absorb.
The intestine transports glucose and fructose via different pathways. When athletes combine carbohydrate sources (often in a 1:0.8 or 2:1 glucose-to-fructose ratio), they can oxidize more total carbohydrate per hour. This is what allows intake to climb toward 90–120 g/hr in some cases.
However, higher intake doesn’t automatically mean better performance.
Higher fueling rates work best when:
- The event lasts 2.5–3+ hours
- Intensity is high enough to rely heavily on carbohydrate metabolism
- The athlete has practiced fueling at that rate in training
- Products contain multiple transportable carbohydrates
- GI tolerance has been developed gradually
It may not work well when:
- The athlete hasn’t trained the gut
- Intake is increased suddenly on race day
- Effort level is low enough that fat oxidation covers much of the energy demand
- The runner is prone to GI distress
Regarding simple calculations: a body-weight-based estimate can be helpful, but shouldn’t be treated as a rule. A common rough starting point is:
Body weight in kilograms ≈ target grams per hour (for moderate-to-high intensity events over 2 hours).
So a 70 kg runner might start around 60–75 g/hr and adjust upward based on tolerance and race demands.
The key takeaway: fueling is highly individual. Start conservative, practice in long runs, increase gradually if performance demands it, and never try a new fueling strategy on race day.
The goal isn’t just to avoid bonking, but to fuel at a level that supports your specific race pace, duration, and physiology without overwhelming your gut.
How Do You Carry Energy Gels While Running?
There are different ways to carry energy gels during a marathon or long run, such as:
- Tucked in the pocket of your running shorts
- In a hydration pack, flip belt, waist pack, or handheld water bottle
- Pinned to the inside edge of your hat
- Holding gels in your hand
- In compression shorts or half tights with built-in storage pockets
- Wearing an arm sleeve or forearm band with gel pockets
- Using a race belt with elastic gel loops
- Carrying multiple gels decanted into a small soft flask
- Taping gels flat to the inside of your shorts to minimize bounce
Are There Any Alternatives For Fueling?
Other sports nutrition or running nutrition products can be used instead of energy gels.
Remember that some alternatives may not provide the same number of grams of carbohydrates, calories, electrolytes, or overall nutrition, so you will need to review the nutrition facts when designing your fueling strategy.
Here are some sports nutrition energy gel alternatives, many of which you can get on Amazon or your local running store:
- Honey Stinger Waffles
- Stroop Waffles
- Gu Energy Chomps
- Sports Beans (some are caffeinated)
- Energy bars
- Energy chews
- UnTapped Maple Syrup packets or similar
- Jelly Babies in the UK
- Sports drinks
There are also alternatives for those who do not like the taste or consistency of gels.
I often recommend trying whole foods alternatives, particularly if you don’t have a sensitive stomach or haven’t had much luck with various sports nutrition-fueling products.
Some of the best alternatives to energy gels for running nutrition include the following:
- Raisins and other dried fruits such as dried pineapple chunks, dates, figs, dried cranberries, and dried apple rings
- Banana chips
- Fresh bananas if you carry a hydration pack or a running vest and have space for larger running fueling options
- Applesauce packets
- Baby food packets are high in carbohydrates, such as mashed banana, sweet potato, pears, apples, oatmeal, etc.
- Maple syrup packets
- Honey packets
- Yogurt-covered raisins
- Jelly beans
How To Efficiently Fuel Your Race
#1: Practice Your Marathon Fueling Strategy
Don’t wait until race day to experiment with energy gels.
Your long runs are the perfect opportunity to rehearse your exact fueling strategy, including the timing, quantity, and specific products you plan to use on race day. Fueling is a skill, and like pacing, it improves with practice.
Many runners experience GI distress when consuming large amounts of simple carbohydrates, especially at higher intake rates. However, the gut is trainable. By gradually increasing carbohydrate intake during long runs, you can improve your ability to absorb and tolerate fuel while running.
Practicing consistently allows your digestive system to adapt, reducing the risk of stomach issues when it matters most.
#2: Experiment With Different Types Of Fuel
There isn’t a “best energy gel for runners.”
As a marathon runner myself, I have a super sensitive stomach, and I am well aware that certain energy gels work well for me, while others just don’t.
Every runner will have their own preferences regarding palatability, taste, and digestibility for gels, chews, sports beans, sports drinks, or any other type of running nutrition.
Maurtens 100 Hydrogel has no flavor or colors, so it can be a good option for those who just can’t get them down.
Gels come in different thicknesses, from very thick, like a paste, to quite liquid, like a sports drink. Try these different types during your long runs to see which ones work best for you.
#3: Drink Water With Energy Gels
When using traditional energy gels, aim to drink some water with each one. This helps dilute the concentrated carbohydrates, making them easier to absorb and reducing the risk of GI distress.
It also supports hydration alongside fueling, so your body can efficiently transport glucose into the bloodstream and working muscles.
Be cautious about taking gels with sports drinks. Combining the two can significantly increase the carbohydrate concentration in your stomach at one time, which may overwhelm absorption and lead to cramping or stomach upset, especially at higher intake rates.
That said, not all gels are the same. Some products — such as isotonic gels (e.g., PowerGel Hydro–style options) — already contain added water. They’re designed to be taken without additional water. This can be helpful if you’re between aid stations or prefer a simpler fueling setup.
Just be mindful that, because they contain more fluid, they may take up more space and add a bit more weight than traditional concentrated gels.
As always, practice with the exact type of gel you plan to use on race day so you know how your body responds.
#4: Use Your Teeth
It is sometimes difficult to open energy gel packets while running, so if you can’t rip them open with your fingers, I sometimes rip them open with my teeth (this is not dentist-approved advice!).
#5: Use Caffeinated Energy Gels Sparingly
If you like caffeine for running to enhance endurance3Guest, N. S., VanDusseldorp, T. A., Nelson, M. T., Grgic, J., Schoenfeld, B. J., Jenkins, N. D. M., Arent, S. M., Antonio, J., Stout, J. R., Trexler, E. T., Smith-Ryan, A. E., Goldstein, E. R., Kalman, D. S., & Campbell, B. I. (2021). International society of sports nutrition position stand: caffeine and exercise performance. Journal of the International Society of Sports Nutrition, 18(1). https://doi.org/10.1186/s12970-020-00383-4 and increase energy levels, consider caffeinated gels.
However, unless you are only having one or two gels on your training runs or during your race, you won’t be able to have caffeinated gels for every gel, as this would be too much caffeine.4Mayo Clinic. (2020, March 6). Caffeine: How much is too much? Mayo Clinic; Mayo Foundation for Medical Education and Research. https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/caffeine/art-20045678 Instead, alternate.
Consider working with a sports nutritionist to develop a marathon-fueling strategy and an overall running nutrition plan.
To accompany your race fueling, check out our hydration guide for runners:
