Energy Gels for Runners – What is the Best Running Fuel?

Energy Gels for Runners – What is the Best Running Fuel?

What is the best running fuel? We all know that your body needs energy to run.  But what type of energy do you need for the distance that you are planning on doing?  And how much? And how often? We are going to have a look at some of the energy gels for runners and look into what is the best running fuel, especially over longer time and distance.

Finding out what energy source works best for you is something you should try and figure out before doing any endurance event.  Trying a new form of nutrition on race day is a sure way to increase your chances of unwanted problems (such as cramps and vomiting).

What Type of Energy do I Need?

Your body uses primarily two types of energy to fuel the muscles when running.  They are carbohydrates (broken down to glucose) and fats.   The body will use protein as an energy source when other sources are depleted, but glucose is the preferred source as it is easily converted to energy.

Some athletes train their bodies over time to utilise their fat stores when racing. This is a complex topic and I won’t be delving into this type of fuelling in this post.  We will look at covering the primary fuel source that the majority of people use which is carbohydrates.

Leaping over the rocks

Carbohydrates are the bodies preferred source of energy. All carbohydrates are broken down into simple sugars which can be absorbed into the bloodstream (ie glucose).  The body is able to utilise this glucose in the bloodstream for energy and any excess is stored as glycogen in the muscles and liver. When the availability of glucose is depleted, the body will then convert the stored glycogen back to glucose for further energy.

Gels, chews or sports drinks are the most popular products for athletes to ingest when long distance running. They are easy to store and easy to take on the go. It is important to experiment with these products in training to see what works for you. Everyone is different, what works for one person may not work for another.  Experiment in training first and once you have found something that works well for you, stick to it.  Definitely do not try something new on race day!

My preferred Gel products are-

High 5 Energy Gels

SIS Isotonic Energy Gels

Another popular brand is GU Energy Gels.  Personally I find them a bit thick in consistency, unlike the other two which are more fluid like. But they are worth a mention as they are popular in the endurance world.


Energy Used During the Run

Once the available glucose in the bloodstream has been taken up by the cells, the body will convert any stored glycogen back into glucose.  The body will only be able to store a certain amount of glycogen (even with an optimal “carb loading” program pre event).

For example, when running at marathon pace we have approximately 90 minutes of available stored glycogen.  This of course will differ slightly person to person.  So even if you are an elite runner you will need some type of fuel source when you are running more than 90 minutes (particularly if you want to see optimal results).

How Many Gels?

Long run

When taking Gel’s or chews it takes approximately 15-20 minutes (which can differ from person to person) to utilise the glucose once it has been ingested (for it to reach the bloodstream and be available to the cells). Once running, it is important to have your next energy source around the 40 minute mark to hopefully reach your muscles by the one hour mark.

Now it is important to be aware you can’t refuel yourself the same way you do your car. The body can only metabolise 25-60g of carbohydrate per hour.  (Again, a variable thing person to person).

To add another complication to the whole process, the body requires more than this amount of carbohydrate per hour when running.

If you try and force down more than what the body can take on you are certain to encounter problems such as stomach upsets, cramps, etc.  Basically the body will start to refuse the excess (blah!)

In most types of gels there are approximately 30g of carbohydrates.  In most cases that means two gels per hour maximum. So by calculating/estimating the time it will take you, you can work out how many gels will be required in a run that is longer than 75-90 minutes.

Lately I have been using the edible chews.  As I am running longer distances and therefore at a slower pace, it is much easier to consume this energy source in this form. For shorter distances, I am running at a faster rate and  I find these harder to swallow.

GU Energy Chews


CLIF Energy Bloks

What About Natural Options?

If you would like to use wholefoods like dates and bananas, you will have to estimate the amounts you will need with some research, and trial and error during training.  When you are running for more than four hours it is also a good idea to look at taking in actual food for fuel.  Once an event goes for over four hours, taking in gels alone will be difficult and can be hard for the stomach to take.

Popular choices are bananas, dates, nuts and dried fruit. Just make sure it’s not something that may get destroyed during the run.

Longer Runs

Long run

If you are in an event with aid stations where you can leave nutrition and hydration, there are more options in the way of nutrition.  Things such as sandwiches (peanut butter, jam), mashed potato and rice snacks.

Again this will be an individual thing and something you will have worked out during your training. High fibre foods are best avoided as they are more difficult for the body to digest and are more likely to cause an upset.

Other Nutritional Considerations

Another factor to consider when running longer distances is the loss of salt from your body through sweat. This will depend mainly on the amount of sweat lost during a race.

When running on days of hot weather or for longer than 2  hours you will need to look at replenishing your salt supply.  Products like SaltStick Capsules which are basically capsules filled with Sodium, Potassium, Calcium and Magnessium and electrolytes such as SIS Go Hydro Hydration Tablets dissolved in water can help with this. You can read more about this topic in the article Best Salt Tablets For Runners.

So Important Factors To Remember are-

  • First gel can be taken 20 minutes before the race.
  • Second gel around the 40 minute mark and then a maximum of one every half an hour after that.
  • Chews intake should be around 4-6 blocks/pieces per hour (if not taking gels).
  • If you are having sports drinks at aid stations, factor that into your 60g carb max per hour.
  • If running over four hours I suggest eating whole foods, bars, sandwiches, mash potato etc.
  • A salt supplement should be taken for long periods of running or in the case of hot weather (eg. salt stick, extra salt on your mashed potato at the aid station).
  • Most importantly – anything you plan to use on race day has been thoroughly practised in training.

Get it Right in Training

Nutrition in endurance races is a very important factor. It is not something that you get 100% right in your first race generally, but you will learn what works for you with practice and making sure you’re getting the basics right while you are learning.

If you have any questions or comments it would be great to hear from you and I will do my best to answer them. Like I said, nutrition is a very individual thing. You have to work out what works best for you over time.

Happy Running,


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