Energy gels for running are single-serve sachets of concentrated carbohydrate designed to fuel runs longer than about 60 minutes. They are light, easy to carry and fast to absorb, which is why you see them at every aid station from parkrun to Gold Coast Marathon. Here is how to use them properly, from an accredited exercise physiologist at our Samford gym.
Why you need fuel on a long run
Your body stores roughly 90 minutes of glycogen at a steady pace. Once that runs low, you slow down, lose concentration and feel terrible. Runners call it “hitting the wall.” Taking carbohydrate during the run tops up the tank before it empties, so you hold your pace longer and finish feeling human.
Energy gels for running: when and how much
For most runners, the rule of thumb is one gel every 30 to 45 minutes once the run passes 60 minutes. That delivers roughly 20 to 30 grams of carbohydrate per serve, which is close to the 30 to 60 grams per hour most runners can absorb.
- Take your first gel at 40 to 45 minutes, before you feel flat.
- Wash it down with water, not a sports drink, to avoid overloading sugar in the stomach.
- Take another gel every 30 to 45 minutes after that.
- Practise in training. Never try a new gel on race day.
Energy gels for half marathon
A half marathon takes most recreational runners 1 hour 45 minutes to 2 hours 30 minutes. That means you will likely need two to three gels. A simple plan:
| When | What |
|---|---|
| 2 to 3 hours before | Familiar carbohydrate-based breakfast: toast, oats or a banana |
| 40 to 45 minutes in | First gel with water |
| 75 to 80 minutes in | Second gel with water |
| 105 to 110 minutes in (if still running) | Third gel with water |
Our half marathon plan builds these fuelling rehearsals into the long runs so nothing is new on race day.
What to look for in an energy gel
Not all gels are equal. Here is what matters:
- Carbohydrate source. A mix of glucose and fructose absorbs faster than glucose alone. Check the label for maltodextrin plus fructose.
- Caffeine. Some gels contain 25 to 50 mg of caffeine. Useful in the second half of a long race, but try it in training first because it can upset the stomach.
- Consistency. Thicker gels need more water to get down. Thinner, isotonic gels can be taken without water but tend to cost more.
- Taste. You will eat several of these. Pick one you can stomach after 90 minutes of running.
Real food alternatives
Gels are convenient, but they are not compulsory. Plenty of runners fuel long efforts with real food instead:
- Dates or dried apricots (roughly 15 to 20 g carbohydrate per small handful)
- Jelly lollies or jelly beans
- White bread with honey, torn into quarters
- A banana, carried in a belt
The same timing rules apply. Whatever you choose, rehearse it on your long training runs. Our guide to the best pre workout snack covers what to eat before you head out the door.
Common mistakes
- Waiting until you bonk. By then it is too late. Start fuelling early.
- Drinking sports drink with a gel. Double sugar often means stomach cramps. Use water.
- Skipping fuelling in training. Your gut needs practice absorbing carbohydrate on the move, just like your legs need practice running long.
- Using gels for runs under an hour. You do not need them for short sessions. Water is enough.
Hydration alongside gels
Gels replace carbohydrate, not fluid. You still need to drink. For runs over an hour, sip water at every aid station or carry a small bottle. On hot days or if you are a heavy sweater, an electrolyte drink between gels helps replace the sodium you lose in sweat. Our marathon running plan covers fuelling and hydration across a full 16-week build.
When to get it checked
If you regularly feel nauseous or uncomfortable on runs despite following a sensible fuelling plan, it is worth getting assessed. Gut issues during running are common, and an exercise physiologist can help you work out whether it is timing, volume, concentration or something else. We see this a lot at our Samford clinic, especially in the months before a big event.