The Biggest Fueling Mistake Endurance Runners Make

I have a friend named Matt who is an incredible ultra runner. And when I say ultra runner, I mean the long ultra distances — 200 and 250 miles. Over the years, I’ve heard him drop plenty of little nuggets of ultra wisdom, but one has stuck with me more than the rest:

“In ultras, the answer is almost always food.”

Something feels off? Try food.

Getting cranky? Try food.

Ready to quit? Try food.

Questioning every life choice that led you to this moment? Honestly, still maybe food.

Obviously, food doesn’t solve everything. Sometimes the answer is pacing. Sometimes it’s sleep. Sometimes it’s electrolytes. Sometimes it’s a 10 minute dirt nap.

But for endurance runners, underfueling is often the boring answer nobody wants to look at first.

And I’d argue this doesn’t just apply to 200-mile runners. It applies to marathoners, half marathoners, trail runners, and anyone asking their body to show up for training week after week.

Through the race. Through the training. On a random Tuesday.

Are you eating enough to support everything you’re asking your body to do?

I finished my second 50k in November 2024 at Mamba 100 in Memphis, TN

Eat Like Your Mileage Has Changed (Because It Has)

Showing up to your race fueled and ready starts long before you hit the start line.

As your training builds, your food intake usually needs to build with it. You’re asking your body to run more miles, recover from harder efforts, adapt to training, support muscle, manage stress, and still function like a reasonably pleasant human. 

That takes fuel.

Trying to maintain your normal food intake while your mileage climbs can lead to exhaustion, sluggish runs, poor recovery, mood swings, intense cravings, uncontrolled overeating, and sometimes injury.

And I get it. A lot of runners worry that eating more will automatically mean gaining weight.

But being constantly underfed while training hard can backfire fast. Your body may eventually boomerang right past the amount of food it actually needs and send you into “eat the entire kitchen” mode.

I’ve seen it happen. I’ve lived versions of it. It’s not a willpower problem. It’s an underfueling problem.

As your mileage ticks higher, start looking at whether you need more carbs, more protein, or simply more total food. You don’t have to overhaul everything overnight, but your fueling should grow with your training.

And if you have no idea where to start, this is exactly where a friendly neighborhood nutrition coach comes in handy.

We were keeping track of how much my husband was eating during his first 100 miler by collecting his trash at each aid station. (And yes, he fuels ultras with cheeseburgers!)

Eat Before Your Fuel Gauge Hits Empty

Every runner has their own routine on race day.

Some get up several hours early, eat breakfast, and go back to bed for a bit. Some are eating a banana on the way to the race. Some runners deal with stomach discomfort if they eat too close to the start.

Figuring out what works for you matters. And that means practicing different scenarios during training, not experimenting for the first time on race morning. Have I mentioned the golden rule of running? Nothing new on race day.

During endurance running, food becomes your new best friend. Whether it’s gels and chews during a road marathon or a peanut butter and jelly sandwich during a 100K trail race, keeping fuel coming in is crucial for a strong race and better recovery.

Our second half-marathon

As a real-life example, let me tell you about my second half marathon.

I was excited, nervous, and ready to toe the start line — but I had a fueling plan. Every 35 minutes, I would take a gel.

I found my pacer, the race began, and I felt GREAT. Invincible, even. I was running faster than I ever had during a race.

And then I looked down at my watch and realized I had missed my first fueling time by quite a bit.

I shrugged it off, took a gel, and kept going.

By the last two miles of the race, it was time for another gel based on my adjusted schedule, but I decided I didn’t really need one with only two miles left.

Famous last words.

Shortly after that, the pacer started pulling away.

At first, I wondered why she was speeding up. Then I looked at my watch and realized she wasn’t going faster.

I was getting slower.

The pacer kept pulling away, and there was absolutely nothing I could do to catch up or keep up with her. I finished the race, but it wasn’t pretty.

That race taught me a lesson I still think about: you need fuel consistently during endurance events. Even if you feel good. Even if you’re excited. Even if there are only two miles left.

You need fuel before you feel empty.

Recovery Matters as Much as Fueling for Endurance Runners

Fueling your body after a long run or race is just as important as eating before and during the run.

Your body has been through a lot. You’ve burned through glycogen, broken down muscle tissue, lost fluid and electrolytes, and asked your body to do hard things for a long time. It deserves the nutrients it needs to repair and recover.

A good recovery target is to get some carbs and protein within 20 minutes to 2 hours after you finish.

Carbs are your friend.

Protein is your friend.

Hydration is your friend.

And yes, actual food is your friend too.

A recovery shake or bar can be helpful, especially on the drive home, but it usually shouldn’t be the entire recovery plan.

If you’ve fueled well during training, before the race, during the race, and after the race, you may notice less of that bottomless-pit feeling later. Recovery may still feel like recovery, because running long distances is not exactly a piece of cake.  

Fueling well doesn’t make endurance training easy. It gives your body a fighting chance to do what you’re asking it to do.

You don’t need to earn your food with miles. You need food to support the miles.