Fueling for Long Runs & Races

I’ll split this up into a few points:

1- How many calories or grams of carbohydrates do we require while on a long run or race?
2- Where do we get these calories from?
3- How do your caloric requirements change the longer you go?

· How many calories do we need for one long run or race?

The general consensus for sustained endurance activity over 1 hour is 200 cal per hour or 50g of carbohydrate per hour.

This is a good starting point. For example, I can go for a 2-hour easy intensity run pretty comfortably without needing any calories. For this distance, I focus on hydration only – 500 ml of water. 

But, if I head out for a higher intensity workout (e.g. half marathon session up to 2 hours) then things start to change! For this, I would take on a couple of gels across the workout – probably around the 40-minute mark, then again at the 1-hour 15 min mark. Or, I would add Tailwind to my water. 

My hydration requirements would also go up due to the higher intensity, so instead of 500mls of water, I’d probably increase this to 700 – 800mls depending on the temperature.

Sure, I could still do a higher-intensity workout for 2 hours without hydration or calories, but based on the experience I’ve built up over the years this would be detrimental to my overall recovery and readiness for my next training session. 

Fun fact: The calories we take in while we’re training fuel both that session and our recovery.

If you’re new to fueling while running then you will want to start dabbling once you get beyond 1 h 15 min of running. Even if you’re only going out for 1 h 30 mins, start by having a gel around the halfway mark.

Another fun fact: Training is a full-body experience. You need to train your gut too!

· Where do you get your calories from?

This can be based on personal preference but the general rule of thumbs is this:

Say you’re running a marathon at or below 3 h 30 min. If we take the first and last 30 minutes out (leaving 2.5h) and you’re aiming for 200cal per hour, then you will need 5 gels (100cal each) for that effort. 

You could also run this on 4 gels and top up your calorie intake with some liquid fueling. Aid stations usually offer something that hits the mark. Like Coke! (I love Coke for racing!) 

Beyond the classic gels, there are lots of variations. Some have caffeine, some don’t. Some are mixed with liquid, some aren’t. Then you’ve got actual food! (think pizza for an Ultra!) 

There are all sorts of electrolyte drinks, like Tailwind (also liquid fueling – 100cal per scoop!) that you can use exclusively during a race or long run. Tailwind is great if you suffer from GI distress from the intake of other calories while running.

I find Tailwind is perfect for super hot conditions where you need hydration and calories but eating feels like a tall order!

Again, this is all personal preference so just do what works best for you. 

But remember, figure out what your body needs early in your training sessions. Don’t leave it too late to start experimenting!

Side Note about Caffeine:

Many gels, chews, and fluids have caffeine in them. Be sure to keep an eye on the packaging! 

My preference for caffeine and racing is to introduce it during the 2nd half of a race, particularly if it’s an Ultra; this is when you’ll find me reaching for the Coke! But, if I’m running a half marathon then I might take some on earlier. 

I find that I have to be careful about how I use caffeine in a race. Usually, it works great, but I’ve also had it backfire on me and ended up in a state in the bush. Think 21 hours into a 100-mile race at midnight! Not pretty!

· How do your caloric requirements change the longer you go?

From my own racing experience and feedback from runners and athletes that I coach, I have noticed that our needs change once we get past the 3.5 – 4 hour mark. 

Let’s talk road marathon: Most runners can run a 3.5/4-hour marathon on gels/chews and a combo of things they grab at the aid stations. But once you run beyond 4-hours you are entering new territory. A territory where your gut might reject the sweet stuff. 

So, if you’re planning on being 4+ hours in a marathon, consider introducing some endurance-type food into the mix. Your gut will be happier and you will be more likely to hit that 200cal per hour requirement. Believe me, an unhappy gut and inadequate fueling will make for a very tough day at the office!

Once you get over the 6-hour mark, like an Ultra Marathon, things seem to change again! 

If I’m going on a 6-hour run, I’m quite happy on a rotation of gels, Cliff Bars, and Tailwind. I can very comfortably meet my caloric and carbohydrate needs. 

6-8 hours I’d likely add Coke into that mix. 

8+ hours (for me that’s a 100k/100Mile Race), then not only will other foods be in the mix, but they will be in the mix from the very start of the race. A nice rotation every 20 mins on average. Little and often is key!

So, what other food do you use in an Ultra? (8 + Hour Effort)

This is the personal quest of each Ultra runner to find out for themselves! 

I like good danish, bananas, and salty crisps. If I’m going super long (say 18 + like 100 Miler or Mountain 100k), then things like wraps, pizza, mince, and rice will start to find their way in at aid stations or crew meet-ups once I get past 12 hours. 

The longer I’m going, the more FOOD that starts to make its way in. Also, the more protein/fat I start to crave.

Not heaps, small bits at a time. There comes a point where you just feel like something that is going to satisfy your taste buds and give you a break from packet endurance fuel stuff! 

So, if you’re training for a 12-hour + effort, start experimenting with these different foods during your 6-8 hour outings. You’ll soon get to know what works for you.

Takeaway Tips:

  • Practice everything you intend to do on race day during training. Don’t try anything new on race day, whether during the race or your pre-race breakfast!
  • Practice all aspects of your race fueling in a training simulation. If you are training for a half marathon or marathon, and you’re on the faster side of things, make sure you practice fueling at ‘race pace. The mechanics of fluffing around with gels or fluids, not to mention stomaching them, can be a whole new ball game at speed!
  • If you are competitive in the half and full marathons and you’re relying on aid stations for water, then practice drinking out of those cups at speed. Trust me, it’s a challenge worth practicing!!
  • If you’re training for a big Ultra then be sure to train at different times of the day and night. Everything works differently at different hours!

The biggest piece of advice: Practice EVERYTHING you’re going to do on race day in training.


  1. Aimee on July 18, 2022 at 12:46 pm

    Brilliant advice as always Chris!! I totally rate Tailwind!

  2. Lindy on December 16, 2022 at 8:33 am

    Thanks Chris, super helpful. Might try some tailwind for my longer runs.

  3. Elize on December 16, 2022 at 9:31 pm

    Awesome advice, thank you. I’ve found tailwind, 1/4 of a cliff bar and nuts are my go to, with occasional gel or even a peanut butter and cheese sandwich ????

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