How to Fuel for the Long Run

By Karen Poole

Photo via Clif Bar at

When you run a 5k, 10k or even a half marathon, you may be able to get through the entire run by simply hydrating. When you jump to training and running longer distances, like the marathon and further, you will need to bring a more solid fuel. 

Energy stores are depleted the longer you run, causing you to slow down or hit the wall. Replenishing your energy stores before you start to feel a crash coming on is essential to performing your best during a race. Discovering why, how, when, and what to fuel with is a process that often varies from person to person. Here’s what you need to know about fueling on the run so you can get that PR!

Why Fuel

Fueling is not only recommended, it is scientifically proven to be a necessity in training. Our bodies use glycogen for energy. During the run, our body has a limited amount of glycogen to supply energy to working muscles. For the average person, this equates to about two hours of intense marathon training before we run out of glycogen. Fueling before we deplete our glycogen stores can be the difference between crashing out and achieving our goals. 

Learning how to fuel and when to fuel differs for many people. Practicing fluid and nutrient intake during your long runs will be crucial to race day success. If you eat too many carbohydrates your body may be unable to digest them properly and you will feel bloating and cramping. Practice will help you discover the precise amount of carbs to keep your blood sugar level steady throughout your entire race. 

Learn more: Should I use gels to fuel my long run?

How to Fuel

Generally, before you begin a race you will have eaten a small breakfast. During the first hour of running, you won’t need additional fuel. As the run goes on you will fuel more regularly. Every hour, after the first hour of running, runners will ingest between 100-250 calories or 25-60 grams of carbohydrates. If you are a newer runner, you may need slightly more calories because your body isn’t as efficient at running yet. Veteran runners may get by with fewer calories per hour. 

An important thing to remember is to fuel before you feel your energy crashing. Scheduling your fueling will help you avoid a big energy crash. I tend to eat 1-2 energy chews every 20-30 minutes on the long run or for the duration of the race. This keeps my energy level high. You don’t want to wait much more than 30 minutes between each fueling session because you are expending energy too quickly and if you wait too long you will start to feel your energy crash sooner. 

What to Use for Fuel

Make sure you test different brands to find what is right for you. The worst thing you can do is test out your fuel on race day, like I once did. About 6 years ago I ran my first trail 12k race. I didn’t bring fuel with me and decided to test what was on course halfway through the run. It was a vanilla gel and I took one bite and felt sick. The texture and flavor did not mesh with my palate and I had stomach troubles for a few miles as my system tried to process this new fuel. Moral of the story? Listen to veteran runners when the say “nothing new on race day” and practice, practice, practice! 

Practice makes all the difference. Had I tested the fuel that was going to be on course during my training runs I would have already known it was not the right fuel for me and could have avoided race day discomfort. It’s much better to discover what works or doesn’t work during training than suffer the consequences later.

Go to a local running store and purchase 5 or 6 different types and brands of fuel (gels, chew, waffles, bars). Test them out over the course of your distance training. Try a new fuel during each long run until you find the one that works best for your body. You’ll discover pretty quickly what works for you. 

Some recommended and commonly used running fuels are:

ProBar Bolt Energy Chews (My Favorite!)
Scratch Labs Energy Chews
Gu Energy Gel
Clif Shot Bloks
Honey Stinger gels, chews, or waffles

Where to Stash Your Fuel

Now you know how to fuel. But where do you put it all? When I run a marathon I often stash my fuel in the zip pocket on the back of my pants. If there isn’t enough room there you can get a waist belt to carry extra gels or chews. FlipBelt, Fitletic, and most running accessory companies make great options. Check out your local race expo to try on different models to find the best one for you. When looking for a waist belt you want to make sure you get one that fits your hips and won’t ride up or down on the run. 

Don’t be afraid to get creative either. As a woman, that sports bra makes an excellent space to stash your fuel. Or put a few gels in the waistband of your running tights. You want your fuel to be easily accessible and not bothersome, so find what works best for you through a little trial and error. 

Race day nutrition and fueling is all about practice and discovering what works for you. Once you discover which fuels keep your digestive system happy, work on perfecting your fueling schedule and continue to practice throughout your training. Come race day you’ll be a pro and the only thing you will be worried about is crushing your goals! 

Learn more about race day nutrition and hydration using the links below: 

Karen Poole is a RRCA certified running coach, personal trainer, and lover of all things fitness! She believes that dark chocolate and a good run can solve most problems. You can follow her on Instagram at @superwomankw