02 Feb Why Nutrition for Runners Matters (more than you might think)

Why Nutrition for Runners Matters (more than you might think)

If there’s one topic that sits at the absolute core of my work as a dietitian and running coach, it’s this one: nutrition matters.

Not just a little. Not just on race day. And not only for elite athletes.

Nutrition matters for your performance as a runner, for your recovery, for your long-term health, and honestly, for how you feel as a human being day to day.

If you’re a long-time listener of The Fuel Run Recover Podcast, this probably isn’t new information. But if this is the first time you’ve landed on my website or heard my name, I want you to know this: this post is for you.

And if you are already familiar with my work, consider this a reminder and a reassurance — caring about your nutrition is not “extra.” It’s one of the most valuable investments you can make in your running and your health.

Why I Created the Runner’s Fueling Audit

One of the reasons I wanted to talk about this topic in more depth is because I recently launched a free Runner’s Fueling Audit — a short yes-or-no assessment designed to help runners reflect on their day-to-day fueling habits.

It takes less than five minutes from start to finish, but it can be incredibly eye-opening.

The audit looks at:

• Common signs and symptoms of underfueling
• Meal timing around training
• Frequency of eating throughout the day

These are things I work on with clients all the time, and they matter far more than most runners realize.

Before we talk about what to do differently, we need to understand why nutrition for runners matters in the first place.

Eating Enough: The Most Overlooked Performance Strategy

The first — and most important — piece of the puzzle is simply eating enough to support your training demands.

Most runners are surprised to learn that the majority of the calories we burn each day have nothing to do with exercise.

Even if you did absolutely nothing all day — no running, no walking, no chores — your body would still require a significant amount of energy just to keep you alive. Your brain, heart, digestive system, hormones, enzymes, and cellular processes all require fuel.

Unless you’re training for hours every single day at a near-professional level, your resting energy needs are the biggest slice of the calorie pie.

When there isn’t enough energy coming in, something has to give.

And that’s when we start seeing problems.

What Happens When You Don’t Eat Enough as a Runner

When runners don’t fuel adequately, the impacts go far beyond “feeling tired on runs.”

You might also have issues with:

• Digestive health (bloating, constipation, diarrhea, gut discomfort)
• Brain function (brain fog, poor concentration, mood changes)
• Hormone production
• Recovery and injury risk
• Training quality and performance

Your brain alone uses a massive amount of energy each day. When runners describe feeling low energy, foggy, moody, or chronically fatigued, one of the first things I want to assess is whether they’re eating enough to support both training and basic body functions.

Low energy availability can impact the health and function of all body systems

In sport nutrition, we call this state low energy availability — when there simply isn’t enough energy to go around.

Left unaddressed, this can progress into Relative Energy Deficiency in Sport (REDs), which impacts nearly every system in the body.

And despite what many people still believe, this doesn’t only affect female athletes. We now know it affects runners of all genders, ages, and athletic abilities. However, it’s important to note that endurance athletes are at higher risk of this compared to some other sports, due to how many hours per week it takes to train for our events.

“You’re Not Eating Enough” — The Conversation No One Expects

I’ll never forget the first time I told a client I didn’t think she was eating enough.

She looked at me like I was completely out to lunch.

And honestly, I get it.

Most of us grew up hearing the same message over and over again: eat less, move more. So being told that eating more might actually be the missing piece feels counterintuitive — even threatening.

But after more than a decade working in this space, I can tell you this: underfueling is one of the most common reasons runners feel stuck, injured, exhausted, or frustrated with their progress.

Calories Matter — But Macronutrients Matter Too

Even when runners are eating enough overall, nutrition can still be holding them back if the macronutrient balance is off.

Carbohydrates, fats, and protein all play different roles:

• Carbs and fats are primarily used for energy
• Protein is essential for repairing and rebuilding tissues

One of the most common patterns I see is runners eating enough calories, but far too few carbohydrates for their training volume.

Low-carb diets cycle in and out of popularity, but for runners, chronically low carbohydrate intake often means:

• Poor workout quality
• Difficulty hitting higher intensities
• Feeling like every run is “hard” even when fitness should be improving

Here’s a key point I want runners to understand:

A workout feeling hard doesn’t always mean you’re training effectively. Sometimes it just means you’re underfueled.

When carbs are too low, protein can get diverted into energy production instead of being used for recovery, hormone production, and tissue repair. The body is incredibly adaptable — but it can’t make energy out of nothing.

Research even suggests that low carbohydrate availability can mimic many of the symptoms of low energy availability, which tells us just how critical carbs are for runners.

Micronutrients: The Missing Layer of Performance Nutrition

Beyond calories and macros, nutrition quality matters.

Vitamins and minerals like:

• Iron
• Vitamin B12
• Calcium
• Magnesium
• Potassium
• Omega-3 fats
• Zinc

don’t provide calories, but they play massive roles in performance, recovery, bone health, oxygen delivery, and overall function.

You can technically meet your calorie and protein needs while still being deficient in key micronutrients — especially if most of your intake comes from convenience foods or supplements like protein bars or shakes rather than whole foods.

This is why performance nutrition isn’t just about “hitting numbers.” It’s about supporting the body from the ground up.

Why Understanding Nutrition Helps You Ignore the Noise

One of the biggest benefits of understanding your nutrition needs as a runner is confidence.

When you understand why you’re eating the way you are, you stop chasing diet trends. You stop piecing together random advice from social media. You stop reacting to every hot take designed to grab attention rather than help you.

Social media has changed — and not always for the better. Engagement often matters more than accuracy, and extreme opinions travel faster than nuanced, evidence-based advice.

But when you understand your body and your fueling needs, you can tune out the noise and focus on what actually works.

And that’s where real, sustainable progress happens.

Where to Start If This Sounds Like You

If you’re reading this and thinking, “Yep… this might be me,” I want you to start with the free Runner’s Fueling Audit.

It’s quick, reflective, and gives you a clear picture of where your fueling habits may be supporting — or limiting — your running.

From there:

• If you just need a tune-up, small adjustments can make a big difference
• If you’re struggling more deeply, there are multiple ways I can help

You can start with my ebook Fuel Smarter, Run Stronger, join the Fuel Train Recover Club, or reach out about 1:1 coaching if you’re looking for a fully personalized, science-backed approach.

You don’t need to stay stuck, exhausted, or frustrated with your running.

Nutrition is powerful — and when it’s aligned with your training, it can change everything.

Want to read more about how to fuel for your best runs yet?

What to Eat Before You Run: A Sport Dietitian’s Guide

What to Before, During, and After Your Long Runs

Why Nutrition for Runners Matters (more than you might think)