Why, how and when use energy gels?

To be able to sustain a long cardiovascular effort, your body needs you to provide it with something that can be used as fuel: the carbohydrates. One very common way (and my favorite personally) to do so is to have energy gels during your activity.



When you start doing long runs, either just for fun, or as part of training for a race, come all the questions about the famous “energy gels”. There are so many different brands and types of gel, that one can easily get confused, trust me, I’ve been there: which brand? How many per run? With or without caffeine? Do they all have electrolytes? Isotonic or not? With glucose or 2:1 glucose and fructose?

There are no right or wrong answers. At the end, it is mainly about personal preferences, needs and goals. But still, there are some general rules and guidelines that can help you to make up your mind.


First let’s have a look at the main characteristics of the gels:

The water and the electrolytes:
Some gels need to be taken with a sip of water, some don’t (in that case they are called “isotonic”, but it is not often clearly written on the packaging). That depends on the thickness and the concentration in electrolytes (salts, for example: Sodium Chloride, Sodium Citrate, Potassium Chloride) of the gel.

The sugar:
Some gels contain maltodextrin (glucose) mixed with fructose (which raises the blood sugar levels more gradually than glucose) with a 2:1 ratio, some contain only glucose. But most of the time they have both.

The caffeine:
You can also find gels that contain caffeine for an extra boost, if your stomach can take it as it is also a diuretic.


Then there are other criteria that you can take into consideration based more on the packaging: whether or not it is easy to open without spilling half of it on your hands (when you are running or cycling you want something practical on that matter), easy to hold and to carry, etc…



What, when, how:

Which one?
There are a lot of different brands (Clif, GU, Power gel, SIS, Torq, just to name a few) and the only way to know which one will work the best for you, is simply to try them.

BUT, the most important rule here is to always try them before your race, to test your stomach tolerance. The taste, texture, and effects, can be completely different from one product to the other, and you don’t want to feel sick on the day you spent weeks and weeks getting ready for, with something that is not right for you.

Not before 30 to 60 minutes after the start of the run, depending on what you had for breakfast before and your needs.

Sometimes you can see people starting to take gels even on the starting line of a race. That is definitely something I would avoid doing. Too much sugar too soon, can really mess up your digestive system, and the release of insulin that comes with that excess of sugar will actually drop your blood sugar levels and make you feel tired. Energy gels are here to help you sustain a long effort by refilling a deficit in your energy stock, not to overload those stocks. Too much, at the wrong time, won’t help.

On that matter, be careful if you also take energy drinks as well as gels during your run, as this might also lead to an excess of sugar.

How many?
There is a general rule that says that your intake shouldn’t be more than 1g of sugar / kg of body weight / hour.

How I do it:
I usually start taking gels between 1h15 and 1h30 of running (either on half-marathons and marathons). And from there I try to stick to 1 gel every 45 min average. But again, that is what I feel works the best for me, and it doesn’t necessarily mean that it works the same for you. Some people will need more, some less. Testing and experimenting is also a way to learn more about yourself, and how to optimize your performance while taking care of your health.


My favorites:
After having tried a lot of different brands, my favorite ones are definitely those 3 flavors from the Torq brand: raspberry ripple, strawberry yogurt and banoffee (which contains also caffeine).



I love them because of:

– The texture: smooth and easy to swallow, you don’t need to drink water to absorb them (compare to other gels that stick to your palate)
– The taste: natural (or at least as natural as it can be for a gel), much better than a lot of gels that I tried and didn’t like (too sweet, too artificial)
– The digestion: they are not heavy, even my usually fragile stomach finds them easy to digest.

What about you:

What do you think about gels?
What is your favorite brand?


  • Pierre FELTAIN 10 novembre 2016 at 22 h 56 min Reply

    N’étant pas très expérimenté en matière de gel, j’ai effectivement commis l’erreur de les prendre un peu tôt sur le marathon. Pas sûr que soit l’origine de ma pauvre performance… :))
    Merci pour tous ces conseils qui semblent très avisés et en tout cas je m’en inspire à la prochaine sortie longue.
    À suivre …

  • Vanessa Roux 10 novembre 2016 at 23 h 22 min Reply

    Merci pour ta visite Pierre 🙂 et oui effectivement un gel pas adapte, ou pris au mauvais moment, peut vite nous rester sur l’estomac (la c’est l’experience qui parle! 😛 ), d’ou l’importance de les tester avant la course officielle.
    Quand a ta performance, tu peux en etre fier: tu es un Finisher! Tu auras tout le temps de peaufiner ton chrono par la suite 🙂

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