You’ve heard that you need to fuel your runs but when? How much? What do you fuel with? These questions plus more are going to be what we answer today. Our body only has a finite amount of carbohydrates stored within the body in the form of glycogen. Although the body has enough fat to continue on for a much longer period this is not always what the body needs. When working at any real intensity the body uses carbohydrate stores to fuel the exercise. You might have heard the term hitting the wall, this is when the body runs out of stored carbohydrates and switches to fat burning. Although efficient this leaves you working at a lower intensity than when burning carbohydrates. So let’s dive into what you need to know about fuelling your runs.
What is fuelling your runs?
Fuelling your run is ensuring you take on enough energy to enable you to complete your intended session. Ideally, you also want enough left in the tank that you don’t feel completely wrecked afterwards. This can include taking on food before you run in the form of a meal or snack in the hours leading up to your run. But it can also include taking on carbohydrates during your run.
When is a run long enough to require fuel?
This can vary a little from runner to runner, but the general recommendation is anything over 60 minutes. There is a grey area between 60 and 90 minutes, but the goal is not to finish your run feeling wrecked. With this in mind, it can be better to take on a small amount of carbohydrates during your run. The 60-90 minutes comes in because in general if your body’s carbohydrate stores are full before starting then they will last 60-90 minutes.
So I start taking fuel on after an hour? Right?
Wrong, you want the fuel in your body and available to use before you run out of the stores your body already has. Without doing this you would risk hitting the wall, which let’s be honest none of us want. So although we say anything over 60 minutes you should take on fuel you need to start taking this on much earlier. Depending on several factors such as quantity and length of time running for a planned session, it depends on when you will take on fuel. I always recommend too those I work with to start taking on carbohydrates within the first 30 minutes. This allows the carbohydrates to be digested and absorbed into your body and ready to be metabolised before you deplete your existing stores.
How frequently should I take on fuel during the run?
This depends a lot on the individual runner and the carb content of the fuel source. But somewhere between every 15-30 minutes, it’s probably going to work quite well. Look at the carbohydrates in the fuel you are using and then how much you need in an hour to hit your carbohydrate goal. Then break it up into amounts that suit you. Such as 1 gel every 20 minutes.
How much fuel do I need to take on?
This we can split down into two times; for between 1-3 hours you want to be consuming 30-60g of carbohydrates per hour. For anything over 3 hours you want to be aiming for between 60-90g of carbohydrates per hour. Again the goal here is to finish your run feeling strong so don’t aim for the minimum you want to work your way up to the higher amount. Some athletes are managing 120g of carbohydrates per hour.
What type of fuel should I be using?
Carbohydrates are the main fuel you want to be using and this can come in a number of different forms. You can use gels, drinks, chews, maple syrup, or ‘real’ food to name a few options. Essentially as long as it is providing carbohydrates then it is going to be used by your body. It is a case of finding both what works for you and what you like.
I’ve heard gels give you tummy troubles, is this true?
Some runners can find that gels or certain gels cause them gastrointestinal distress. However, any GI distress can be caused for a variety of reasons including the product not agreeing with them, hydration levels (under or over-hydration), food consumed before running or their stomach just not being used to taking on fuel during a run. So introduce new things slowly.
What does 60g of carbs look like?
| Fuel Source | How much and how often | Number of Carbohydrates per hour |
 High 5 berry (23g per gel) | 1 gel every 20 minutes | 69g carbohydrates |
 Precision Hydration 30g Gel (30g per gel) | 1 gel every 30 minutes | 60g carbohydrates |
 SiSi Orange (22g per gel) | 1 every 20 minutes | 66g carbohydrates |
 +Precision Hydration Carb drink (15g per scoop) 1 Gel (30g) | 2 scoops in 500ml of water every hour (30g) plus 1 gel (30g) | 60g carbohydrates total |
 Dates (approx 16g each) | 1 date every 15 minutes | 66g carbohydrates |
Don’t forget about hydration
To help your body process the carbohydrates it is taking on ensure you are adequately hydrated. This is going to help your performance as dehydration has a negative impact but it will also help your body process what you are taking on.
Summary
- Once you start running for over 60 minutes start fuelling
- Don’t leave fuelling till you feel crappy start within the first 30 minutes
- If running for 1-3 hours aim for 30-60g of carbohydrates
- If running for over 3 hours aim for closer to 90g if not more
- You can mix your carbohydrate sources
- Don’t forget to hydrate
For more guidance on fuelling down my FREE Ultimate Fuelling Guide for Runners here
What personalised support? Then check out my Fuel & Thrive course here
Want to read more about pre-run fuelling? Here is a previous blog post on the topic
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