top of page
  • Writer's pictureJackie K

Long Run Fueling Mistakes

Updated: Mar 9, 2021

Ahh, the long run. Love it or hate it, it's necessary when you're training for a longer race such as a half marathon, marathon, or ultra. Or even if you're training for a shorter distance, you'll likely be doing a run here or there that is longer than what you're training for, or longer than your usual distance.

The long run has so many benefits, including improving your fitness and increasing your endurance. But it takes a lot of work, and a lot of energy! You need to be properly fueled in order to finish a long run, not to mention finish it feeling good.

So many runners don't plan ahead for taking in nutrition and hydration during their long runs. Then the run doesn't go well, and they start to dread running for long distances... or they can't run longer than "x" minutes or "y" miles, no matter how hard they try. And that's frustrating.

So what's going wrong, and what can you do about it?? Here are 4 major long-run nutrition mistakes that I see people make, and how to combat them to win the long run.

Not fueling at all... or not fueling enough.

Have you finished a long run without taking in any gels, chews, sports drink, or other fuel? A lot of runners have... and some of them do it all the time. They'll tell me something like "I don't have to fuel, I do all my long runs that way!"

But then I find out that they feel sick during their long runs or after they're done later in the day. Or that they finish their long runs, but their pace has slowed significantly and they can barely finish.

So what's the deal?

During a long run, you're using up stored energy. This is mainly in the form of glycogen, which is stored carbohydrates in the muscles and liver. The thing is, there is a limited amount of glycogen... and when it's gone, your performance is going to start to suffer. Yes, you still have stored energy in the form of fat, but that takes MUCH longer to convert into something your body can use. So you're basically SOL as your body switches from one fuel source to another... leaving you bonking in the meantime.

You'll feel lousy during the run, your pace will drop off, the effort will feel much harder, and you'll probably feel a lot more lousy later in the day. Not to mention, you could be more likely to have cravings for high carb foods!

So just because you can finish a long run without fueling, doesn't mean that you should. You'll feel better if you fuel.

So what should you do?

You should fuel on any run that's longer than 90 minutes (note that it's time-based, not mile-based!). Your goal is 30-60 grams of carbs (low fat, low fiber) per hour -- that's about 1 gel every 30 minutes. If you want some options that include real food, check out this post where I discuss that.

Waiting Too Long to Fuel

Maybe you don't identify with the people that don't fuel at all. You are someone who brings a gel or some chews, or brings some dried fruit or crackers or something on the run. Despite this, you're still hitting the wall and struggling to hit your paces.

Sound familiar? It could be because you're waiting too long to actually fuel during your long run. Remember the limited amount of glycogen that your muscles store? It only lasts about ~90-120 minutes, and you could start to really feel a decrease in your performance before that.

If you wait to fuel until you start to feel sluggish, then you've waited too long. You're already super low on energy stores... and even if you start taking fuel now, it could take a bit before you start to see the benefits and you might not ever make it back to your pre-bonk performance.

So what should you do?

Again, any run >90 minutes should be fueled. Start fueling about 30 minutes into a long run, and keep fueling every 30 minutes after that. This will keep your glycogen stores topped off and give you plenty of energy to keep going and hitting your paces.

Not Fueling with Water

So you've got your long-run fuel option, whatever it is - maybe a gel, maybe a chew or a waffle, maybe some fruit. You can take it and be good to go, right? Not so fast. Long-run nutrition options are mostly carbohydrates. But you need to be able to absorb these carbohydrates... and if you don't drink water, these high-carb options can be a gut bomb.

Gels and chews are concentrated in sugars -- a much higher concentration than what's in your blood. Your body wants equilibrium... it doesn't want a concentration of sugar to be much higher in one part of the body than another. What happens is your gut will pull water into it to make the concentration of sugar lower, so you can digest it. But that will leave you with GI distress and a stomach ache and possibly running to the port-a-potty.

A word of advice: always drink some water with your fuel. Your gut will thank you!

Not Hydrating On the Run

Did you know that losing >2% of your body weight will lead to a decrease in your performance? For reference, if you're 150 pounds, that's losing 3 pounds on the run. That is pretty easy to do on a long run especially if it is hot and/or humid or you're working really hard!!

And the more dehydrated you get, the more you'll struggle... and the more serious the side effects can get!

You guys, you've got to be drinking water!

So what should you do?

Well, drink water, of course. Use a hydration vest or belt, or bring a hand-held water bottle with you. Plan your route along water fountains, or make loops around your house so you can grab some water on your way. Plan ahead and stash water in strategic places along your route.

Also, know your sweat rate. This is the amount of sweat that you lose in an hour, and it varies greatly from person to person... and changes depending on weather conditions and the intensity of your run too. So test out your sweat rate in several conditions, and re-hydrate on the run accordingly.

Struggling on the long run? Haven't found out exactly what is wrong or how to fix it? I work with runners - like you - to get their long-run fueling strategy right so that they're energized, confident, and ready to tackle race day.

Fuel better, feel better, run faster. To find out how I can help YOU, click to schedule your FREE runner's nutrition strategy session!

99 views0 comments

Recent Posts

See All


bottom of page