If you start running longer distances, sooner or later someone will suggest bringing running gels. At first it can seem unnecessary. Many runners can head out for five or six miles without thinking about food, so the idea of eating while running may feel strange. The reason runners start using running gels comes down to how the body stores and uses energy during endurance exercise.
Your muscles rely heavily on carbohydrates for fuel when you run. These carbohydrates are stored in the muscles and liver as glycogen. Even when your glycogen stores are full, they are limited. Most runners have enough stored energy to fuel roughly 60-90 minutes of running, depending on pace, effort level, and how well they fuelled before the run. As those stores begin to drop, your body struggles to maintain the same level of effort and the run suddenly feels much harder.
This is the moment many runners describe as hitting the wall. Your legs feel heavy, your pace slows, and even concentrating on maintaining rhythm becomes difficult. Taking carbohydrates during the run helps delay this drop in energy by supplying your body with an additional source of fuel while you continue moving.
What Running Gels Provide
Running gels are designed to provide a quick and portable source of carbohydrates during endurance exercise. They come in small packets that fit easily into a pocket, belt, or hydration vest, making them convenient to carry on longer runs or races.
Most running gels contain around 20-25 grams of carbohydrates in the form of sugars such as glucose, maltodextrin, or fructose. These carbohydrates are absorbed quickly and provide energy without requiring much digestion, which is helpful when your body is focused on running rather than processing food.
Some gels also include electrolytes to replace minerals lost through sweat, while others add caffeine, which some runners use later in a race for an extra boost.
Carbohydrate Intake During Long Runs
Sports nutrition guidelines generally recommend that endurance runners consume around 30-60 grams of carbohydrates per hour during prolonged exercise. Some experienced runners who have trained their digestive system can tolerate up to 90 grams per hour during very long races.
Because most running gels contain about 20-25 grams of carbohydrates, many runners take one gel roughly every thirty to forty minutes during long runs. Spacing fuel intake evenly helps maintain stable energy levels and reduces the risk of running out of glycogen later in the run and hitting the proverbial wall. If you have experienced it, you will know it is not pleasant. Your energy drops suddenly, your legs feel incredibly heavy, and even simple thoughts become difficult as your body struggles to keep going without enough fuel.
A Simple Running Gels Timing Strategy
Many runners find it easiest to follow a simple schedule rather than guessing when they need fuel. Waiting until you feel tired is always too late, because by the time fatigue appears your glycogen levels may already be dropping.
A common approach is to start fueling around 30 to 40 minutes into the run and then repeat every 30 minutes. Beginning early allows you to top up your energy supply before your body starts running low on fuel. From there, taking a gel at regular intervals helps maintain a steady flow of carbohydrates to the working muscles.
Following a schedule also removes the need to constantly think about nutrition while you are running. Instead of trying to judge how you feel or remembering when you last ate, you simply take a gel at the next planned point in your run. Many runners find it helpful to link their fueling to time on their watch or to certain distance markers on the course.
For example, during a marathon you might take your first gel around 35 minutes into the race, then continue every 30 minutes afterwards. This approach spreads your carbohydrate intake evenly throughout the run and reduces the chances of a sudden drop in energy later in the race.
It is also important to take gels with a few sips of water, unless you are using isotonic gels designed to be consumed without additional fluids. Water helps the carbohydrates move through the stomach more comfortably and can reduce the chance of stomach upset.
Typical Gel Needs by Distance
| Distance | Typical Time Range | Approximate Gel Strategy |
|---|---|---|
| 10 miles | 75–100 minutes | 1–2 running gels |
| Half marathon | 1:30–2:30+ | 2–3 running gels |
| Marathon | 3–5+ hours | 4–7 running gels |
| Ultramarathon | 6+ hours | Running gels plus additional food sources |
Practice Your Running Gel Strategy During Training
Your stomach needs practice handling carbohydrates while running, just like your legs need practice covering longer distances. Long training runs are the perfect time to experiment with different running gels, flavours, and timing strategies so you know exactly what works for you.
It is also worth remembering that not every gel will agree with every runner. Different brands use different carbohydrate blends, sweeteners, and ingredients, and some runners find that certain gels cause stomach discomfort. Intestinal distress is something many runners have experienced at some point, particularly after consuming too many gels in a short period of time or trying a brand their stomach does not tolerate well.
Training runs give you the opportunity to discover how your body responds. You can test flavours, textures, and quantities to see what feels comfortable while running. Finding out that a particular gel upsets your stomach during a training run is inconvenient, but discovering the same thing halfway through a marathon is far from ideal.
Many large races also provide running gels on the course. Major marathons often hand them out at specific aid stations, but the brand varies from race to race. If you plan to rely on the gels provided by the race, check the race website ahead of time and test those same gels during your training runs.
A fueling strategy that works smoothly in training can make the final miles of a race feel much more manageable, while a poorly tested nutrition plan is one of the fastest ways to hit the wall.
Popular Running Gels Compared
Not all running gels feel the same when you are trying to swallow one at mile 18. Texture, sweetness, caffeine content, and ingredients vary quite a lot, which explains why runners tend to develop strong preferences.
The table below compares some of the most widely used running gels among recreational and competitive runners.
| Brand | Carbs per Gel | Texture | Caffeine Options | Typical Price per Gel (UK) | Notable Features | Gluten Free |
|---|---|---|---|---|---|---|
| GU Energy | ~22g | Thick | Yes | ~£2.15 | Electrolytes and amino acids, many flavours | Yes (most varieties) |
| Maurten | ~25g | Jelly-like | Yes | ~£2.90–£4.20 | Hydrogel technology designed for easier digestion | Yes |
| Science in Sport (SIS) | ~22g | Very thin | Yes | ~£1.70–£1.80 | Isotonic gel that can be taken without water | Yes |
| HIGH5 | ~23g | Thin | Yes | ~£1.49–£1.59 | Light consistency, quick absorption | Yes |
| Clif Shot | ~24g | Thick | Yes | ~£1.50–£2.20 | Organic ingredients, thicker texture | Yes |
The Downside of Running Gels
While running gels are convenient and widely used, they do have some drawbacks that runners should be aware of.
- Very sweet taste
Running gels contain concentrated sugars, which can make them extremely sweet. After several gels during a long run or marathon, the flavour can become difficult to tolerate. - Unpleasant texture for some runners
Many gels have a thick, syrup-like consistency. Some runners find this texture hard to swallow while running, particularly during higher effort sections of a race. - Potential stomach issues
Because gels contain concentrated carbohydrates, taking too many too quickly can sometimes lead to stomach discomfort, bloating, or intestinal distress. This is more likely if a runner has not practised using them during training or tries a new brand on race day. - Can be difficult to open while running
Gel packets are small and can become slippery with sweat. Tearing them open while maintaining your running rhythm can be awkward, especially later in a race when coordination and focus start to fade. - Empty wrappers need to be carried
Once a gel is finished, you still need to carry the empty packet until you reach a bin or aid station. Most races discourage dropping litter on the course. - Relatively expensive
Compared with simple alternatives like sweets, fruit, or cereal bars, running gels are quite costly. For runners who use them regularly during marathon training, the cost can add up over time.
Despite these disadvantages, many runners still prefer gels because they are compact, portable, and designed to deliver carbohydrates quickly during endurance exercise.
Alternatives to Running Gels
Some runners prefer alternatives to running gels, either because they dislike the taste and texture or because they want a cheaper and more natural option. As long as the food provides easily digestible carbohydrates, it can help maintain energy levels during longer runs. Many everyday foods contain similar amounts of sugar to sports nutrition products and can work just as well when used correctly. Popular alternatives include:
- Jelly sweets or candy such as jelly babies, jelly beans, wine gums, or gummy bears, which provide quick sugars and are easy to eat in small amounts during a run.
- Fruit gummies or chewable snacks, which work in a similar way to energy chews and allow runners to spread their carbohydrate intake gradually rather than consuming a full gel at once.
- Rice Krispie bars or cereal treats, which contain simple carbohydrates from rice cereal and marshmallow and can provide a quick energy boost during longer runs.
- Bananas, which are often available at races and provide natural sugars along with potassium.
- Dried fruit such as dates or raisins, which are naturally high in carbohydrates and relatively easy to carry.
- Energy bars or flapjacks, which some runners break into small pieces to eat gradually during longer efforts.
The main challenge with these alternatives is convenience. Running gels are small, lightweight, and designed to be consumed quickly while moving, whereas solid foods may take longer to chew and can be slightly bulkier to carry. As with gels, the best approach is to experiment during training runs to see which options your stomach tolerates best.
Building a Fueling Strategy That Works for You
Fueling during long runs does not need to be complicated, but it does require a little experimentation. Whether you use running gels, sweets, or other carbohydrate sources, the most important thing is finding an approach that keeps your energy steady and works well for your stomach. Practice during training runs so that when race day arrives, your fueling strategy feels just as familiar as your running shoes.
If you are training for a longer race and want more guidance on training, pacing, and nutrition, you can find more advice and support through Achieve Running Club. Structured training, practical coaching tips, and a supportive running community can make the journey to your next race far more enjoyable.
For all your marathon running tips and advice check out Marathon Training Strategies and Running Your First Marathon.
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