Diet TipsRunners Diet

The Impact of The Keto Diet On Runners – Guide to Pros & Cons

14 Mins read

Are you a runner who’s curious about the keto diet but concerned it might affect your performance? You’re not alone.

Many wonder if transitioning from a carbohydrate-based diet to a ketogenic one will impact their running abilities. After all, carbohydrates are often regarded as a runner’s primary fuel source. Let’s delve into this topic.

Think of your body as a car. Until now, you’ve fueled it with premium gasoline (carbs). But what happens when you switch to diesel (fats)?

This is where the keto diet comes in. Initially, there might be a dip in performance as your body adjusts to the new fuel source. However, once you enter ketosis and primarily use fat for energy, things tend to stabilize.

Most experts suggest it takes about three to four weeks for your body to adapt to this new diet. In my experience, it took closer to six weeks before I could run comfortably on keto. The key is consistency and patience. Consider it a long-term strategy.

Today, we’ll explore how the keto diet affects your running—both the positive and negative aspects.

By the end of this article, you’ll have a better understanding of how to integrate a high-fat, low-carb diet with your running routine.

Ready to embark on this journey together? Let’s put on our running shoes and start!

Understanding the Ketogenic Diet: A Runner’s Guide

Before we dive headfirst into the ketogenic diet and explore how it impacts our running performance, let’s start with a basic understanding of the diet itself. Think of this as the warm-up before a marathon, where you familiarize yourself with the course before taking off.

Usually, a typical runner’s diet is rich in carbohydrates, akin to jogging on a well-known and comfortable path. Now, let’s introduce the ketogenic diet, or ‘keto’, as it’s often referred to in runner’s circles. Shifting to a keto diet is like switching from a familiar jogging path to a trail run. In this dietary switch, your body’s primary fuel source changes from the usual carbohydrates to fats. It’s comparable to training your body to adapt to a different kind of terrain in running.

How Keto Differs from Common Runner Diets

So How does the ketogenic stack up against our usual carb-loaded runner’s diet? Grab your water bottle, and let’s jog through this together.

  1. The Carb Feast vs. Fat Fuel: Usually, we’re all about those carb-loading parties, right? Spaghetti dinners before a big race, anyone? In the typical runner’s diet, carbs are the main fuel for our sprints and marathons. But in keto, it’s like inviting a new group to the party – fats. Instead of reaching for pasta, we’re looking at avocados and nuts. It’s a whole different energy vibe!
  2. Flipping the Food Pyramid on its Head: We’re used to the idea that a runner’s plate is mostly carbs – think 60% or more. But keto is like doing a handstand with that plate. Suddenly, fats are hogging the spotlight, making up about 70-80% of what we eat. It’s like training in reverse – a little strange at first, but exciting!
  3. Nutritional Ketosis – The Unfamiliar Finish Line: As runners, we might not be too familiar with ketosis. It’s a state where our bodies, instead of using carbs for energy, start burning fat. Think of it like switching from road running to trail running – a different kind of challenge. Achieving this state requires precise eating, a bit like following a race map to reach that finish line.
  4. The Warm-Up Phase: Unlike our usual high-carb diet, where we can just sprint off the starting line, keto has a warm-up phase. Our bodies need to adjust from being carb-dependent to being fat-adapted. During this period, you might feel like you’re running uphill – a bit tougher than usual. But, just like with any new training routine, it gets easier with time.

One key factor to consider is the intensity of your runs:

let’s talk strategy, specifically about matching your run intensity with your fuel source when you’re on a keto diet. It’s like fine-tuning your race strategy for different terrains.

Low to Moderate Intensity Runs: The Long Haul Fueling:

Imagine you’re out for a long, leisurely run – it’s more about endurance than speed. On keto, these are the runs where you might feel like you’ve hit the jackpot. Your body shifts to using fat for energy, which is like having a larger, more sustainable fuel tank.

It’s perfect for those longer, steadier runs where you’re not sprinting, but cruising. This is the zone where keto-adapted runners can really shine, tapping into their fat stores like a well-oiled machine, keeping the engine running smoothly without the need for frequent carb pit stops.

High Intensity Runs: The Sprinter’s Dilemma:

Now, switch to those high-intensity runs – the sprints, the hill repeats, or those last miles of a race where you’re giving it all.

Typically, our bodies pull from glycogen stores for these quick bursts of energy. It’s like having a nitro boost in a race car.

However, this is where keto runners might face a bit of a challenge. Without those glycogen stores fully stocked, it’s like trying to hit your nitro boost and finding the tank empty. You might feel like you’re running into a wall a bit earlier than usual.

The Benefits of Keto And Running

Here are some of the acclaimed benefits of the keto diet.

Note – Please keep in mind that research on the keto diet’s effectiveness for runners is still inconclusive. Most of the evidence is anecdotal, so take it with a grain of salt.

The Wall and Fat Store

Hitting the wall is like you’ve run into an invisible barrier, and your energy just plummets. This happens because our bodies usually store only about 500 grams of glycogen, roughly 2000 calories – great for a sprint, but not quite enough for a marathon.

But what if we could avoid ‘hitting the wall’? Picture your body like a fuel-efficient car. Normally, we’re running on a small, quick-to-deplete gas tank (glycogen). Now, enter keto. It’s like discovering your car also has a massive reserve fuel tank (body fat) that you never used before. Even if you’re lean, this tank is about 20 times larger than your glycogen stash.

By adapting to a keto diet, where fat becomes your main energy source, it’s like switching to that larger fuel tank. The theory goes that you could potentially skip ‘the wall’ altogether, continuing your marathon as if the wall was just a mirage.

The Potential Magic of Keto: Imagine running a marathon and feeling like you have a secret energy source that others don’t. That’s the dream keto offers. It’s like having a hidden turbo boost in a race. But remember, this is a ‘potential’ scenario. Everyone’s body reacts differently, and keto-adaptation is a personal journey, much like training for a race.

Improved Endurance and Reduced Bonking

We’ve all been there – deep into a run, and suddenly, bam! You hit the dreaded wall, or in runner’s lingo, you ‘bonk’. It’s like your body’s fuel gauge suddenly hits empty. This happens when our glycogen stores, our usual go-to energy source, run out.

But here’s where keto could change the game. When you’re adapted to a keto diet, your body becomes like a hybrid car that can switch fuel sources seamlessly. Instead of relying solely on glycogen, your body starts using fat as a steady, more enduring energy source. Imagine running and having a backup generator that kicks in just when you need it. For long, low to moderate-intensity runs, this could mean you can keep going without the fear of bonking. It’s like having an energy shield that keeps ‘the wall’ at bay.

Finding Your Fat-Burning Sweet Spot

On keto, your body becomes a fat-burning machine. When you’re running at a pace that feels comfortable – not sprinting, not crawling – you’re primarily burning fat for energy. It’s like finding the perfect cruising speed where your body efficiently uses fat as fuel.

For runners who’ve switched to keto, this could mean turning your body into a more effective fat burner, even when you’re not lacing up. Think of it as upgrading your

Additional Resource – Here’s how to create a running program

Improved Body Composition

Let me tell you something about myself.

I’m just like any other runner, hitting the pavement, trying to stay fit. Then, I decide to give keto a whirl. In just the first month, it felt like I was shedding weight as if I was zipping off heavy training gear mid-run. I lost over 20 pounds and saw my body fat percentage drop by over four points. It was like watching my body transform while I trained for a marathon.

Science Backs It Up: But hey, it’s not just my story. Science, our trustworthy coach in the realm of health and fitness, has some insights too. Studies have shown that when you pair the keto diet with moderate-intensity training, it’s like having the perfect running partner. Together, they work wonders in helping you sculpt and tone your physique.

Here are some studies you might want to check out for a deeper dive:

A Notable Study: For instance, a study published in the Journal of Endocrinology revealed something pretty cool. It showed that the ketogenic diet boosts the production of the hepatic growth hormone, a key player in maintaining youthfulness and strength. It’s like finding a natural way to keep your body’s engine running at its best.

Other benefits of the keto diet include:

  • Running on High Octane Energy: Many keto enthusiasts report feeling like they have more energy throughout the day. It’s like your body has switched to a cleaner, more efficient fuel, keeping your energy levels more consistent, without those pesky sugar crashes.
  • Dreamy Sleep: Picture this: you finish a great run, have a satisfying keto meal, and then you drift off into the most peaceful sleep. Many people on keto report better sleep quality – it’s like giving your body the perfect cool-down routine for a restful night.
  • Sharpened Focus: Imagine your mind feeling as sharp as your legs feel on a good run. Keto folks often talk about having enhanced cognition and focus – it’s like your brain is running its own marathon, but with improved efficiency.
  • Weight Loss Wins: We’ve already talked about this, but it’s worth repeating. Keto can be a powerful tool for weight loss, like adding a new, effective workout to your training plan.
  • Sculpting the Runner’s Body: Along with weight loss, keto can help improve body composition – it’s like fine-tuning your body to become a lean, efficient running machine.
  • A Happy, Healthy Heart: There’s evidence to suggest keto can improve heart health – think of it as doing heart-healthy endurance training.
  • Seizure Reduction: For those with epilepsy, keto has been a game-changer in reducing seizures. It’s like finding a secret pathway to better health.
  • Clearer Skin: Who knew that what you eat could make you look as good as a post-run glow? Keto has been linked to improved acne – it’s like giving your skin a health spa treatment.
  • Brain Protection: Your brain loves ketones! Keto may help protect your brain function, making it a great long-term investment for your mental health, like strength training for your brain.
  • PCOS Symptom Relief: For women with PCOS, keto can be a helpful ally, improving symptoms and providing a sense of control, much like nailing a tough workout.
  • And More! The benefits of keto seem to be as varied as different running routes – there’s something new and beneficial at every turn.

Additional resource – Best supplements for runners

The Downsides of Keto While Running

Now, here’s where things get a bit controversial, especially in the world of running.

You see, the keto diet has its fair share of skeptics and naysayers within running circles. And I totally get it – runners have an enduring love affair with carbs. After all, those carbohydrates are like rocket fuel for our runs, propelling us forward with boundless energy.

So, what happens when you start tampering with this vital macronutrient, the lifeblood of many runners? Well, my friends, it’s not all sunshine and rainbows.

I don’t mean to be repetitive, but restricting your carb intake can potentially lead to a host of challenges, particularly when it comes to sustaining the energy levels needed for those long, grueling runs.

Let’s dive into these potential drawbacks so you can make an informed decision about whether the keto path is right for you.

Additional resource – Keto recipes list 

Running Will Feel Like a Drag

Running on keto will suck for the first few weeks. In fact, it can feel like a nightmare. Your body, so used to carbs, now feels exhausted without them. And oh, those carb cravings – they can be like a relentless headwind, pushing against you every step of the way.

But here’s the truth.

This initial phase is a critical part of the process. It’s a sacrifice, like training in bad weather, but necessary if you’re committed to this new path. Remember, it’s okay to let your ego take a backseat. Don’t push yourself to keep up your usual running pace or mileage. It’s like easing into a new training program – start slow, reduce your mileage, and yes, walking is absolutely fine.

Think of it as adjusting your training plan for a new race. You wouldn’t jump into a marathon without proper training, right? The same goes for keto. Take it slow, reduce your runs, and listen to your body. It’s like being in a long race where the conditions have changed, and you need to adapt your strategy.

During this transition, focus on upping your intake of dietary fats – these are your new fuel. Keep your protein moderate, and don’t forget to hydrate well. Think of water and electrolytes as your on-the-run hydration pack, essential for keeping you going.

Like any tough training phase, if you stick with it, you’ll come out stronger on the other side. It’s about perseverance, patience, and adapting to a new way of fueling your body. It might take a while, but just like training for a big race, the rewards can be worth the effort.

The Keto Flu

During early days of the keto journey, you might experience something called the “keto flu.”

Think of it as the initial rough patch of a long-distance race where your body’s still figuring out the pace.

So, what’s this keto flu all about? No, it’s not a flu virus wearing a keto-branded tracksuit. It’s more like your body waving a protest sign because you’ve suddenly cut carbs. It’s adjusting to this new fuel source, and it’s not shy about showing its discomfort.

Here’s a rundown of what you might experience in this initial phase. Brace yourselves – it’s a bit of a bumpy start.

  • Brain Fog: It’s like trying to think clearly while running through a thick mist. Yep, brain fog can be a real hurdle.
  • Irritability: You might find yourself a tad more temperamental, like a runner who’s just missed their morning coffee.
  • Headache: This unwanted guest can be as nagging as a side stitch during a run.
  • Fatigue: Imagine feeling like you’re at mile 20 of a marathon, but you’ve just started your day.
  • Nausea: That queasy feeling might join you, like an unwelcome companion on a morning run.
  • Sleep Troubles: Catching Z’s could be as elusive as trying to nail that perfect race pace.
  • Cramps: Muscle cramps might make an appearance, just like they sometimes do on long runs.
  • Sore Muscles: Your muscles might protest like they’re on a tough training day.
  • Constipation: A bit awkward to discuss, but it’s like when your regular running routine gets disrupted.
  • Dizziness: The world might spin like you’ve just finished a series of speedy intervals.
  • Smelly Breath: Be warned, your breath might pack a punch strong enough to rival your running stamina.

How Long Does the Keto Flu Last?

Just like our running times and experiences differ, so does the duration of the keto flu. For some, it’s a quick sprint – maybe just a few days of feeling off. But for others, it can feel more like an endurance run, lasting a couple of weeks. It’s not a one-size-fits-all situation.

Well, several factors come into play, kind of like how different elements affect our running performance. Your body’s metabolism is one – it’s like your personal pace setter. Then there’s your diet history – think of it as your training log; it influences how your body reacts. And finally, how strictly you stick to the keto guidelines – it’s like following a training plan to the letter. The more precise you are, the more likely you are to see specific results.

Additional resource – Salt tablets for runners

Muscle Loss

While the keto diet is fantastic for helping shed those extra pounds, some of that weight loss might be muscle, not just fat. Why is this a big deal? Well, muscle is like your body’s calorie-burning powerhouse, working even when you’re chilling post-run. Losing muscle is akin to your body downshifting from a high-powered, calorie-burning machine to a less efficient one. It’s like going from a sports car to a slower vehicle in terms of metabolism.

Now, here’s the kicker:

When people wave goodbye to their keto journey, the weight that comes back isn’t always the good kind. Imagine you’ve been training for a race, and then you stop – your body changes, right?

Similarly, when you return to your pre-keto ways, it’s often fat that comes back to the party, not the muscle you lost. It’s like you’ve been training for speed, but then you switch back to leisurely jogs, and your speed gains aren’t what they used to be.

Reduced Performance

Now, let’s talk about something crucial for all you performance-oriented runners out there – the impact of the keto diet on your athletic prowess.

First and foremost, if you’re expecting to switch to the keto diet and immediately start smashing personal records, you might want to rein in those expectations. It’s not a magic bullet for instant performance gains. In fact, quite the opposite can occur.

Carbs, my friends, are like rocket fuel for your body during exercise, especially high-intensity activities like sprinting or intense workouts. They are your body’s go-to source of energy, and when you drastically reduce your carb intake on keto, it’s like asking your car to run on fumes.

Now, here’s the kicker – the research on whether the keto diet can significantly boost your running performance is still in its infancy. We’re talking the equivalent of a toddler stumbling around the woods – a lot of uncertainty.

That said, it’s not all doom and gloom for keto-loving runners. There’s a glimmer of hope, especially for those of you who rack up the miles at a steady, moderate pace. Think marathon runners or those who prefer long, endurance-based activities.

Here’s why:

When you’re logging those miles at a lower intensity, your body can tap into its fat stores for energy. Remember, fat contains a boatload more calories than glycogen (carbs’ stored form).

So, theoretically, you might avoid hitting the wall during longer, slower efforts.

However, and this is a big “however,” when it comes to high-intensity exercise that demands quick bursts of energy, like sprinting or short, intense races, the lack of glycogen can seriously cramp your style. You might find yourself unable to perform at your usual peak, which can be frustrating.

But at the end of the day, it’s your call to make. And hopefully you make the right call.

Additional Resource – Why is my running not improving

When Not To Keto

Runners, let’s hit pause and consider when the keto diet might not be the best fit for our training goals. It’s like choosing the right kind of workout for the race you’re preparing for – not every strategy suits every type of race.

Keto and Explosive Power Sports: Picture this: sports like sprinting or powerlifting are all about short, intense bursts of power – like a quick, all-out sprint to the finish line. In these scenarios, ketosis might not be your ally. Why? Because these explosive movements often rely heavily on glycogen (stored carbs) for that immediate energy surge. It’s like needing a quick burst of speed, but your glycogen ‘fuel tank’ is running low.

Keto for Distance Runners: Now, let’s talk about you, the distance runner, gearing up for a big race or logging those high-mileage weeks. In this case, you can actually tweak your keto diet to better suit your needs. Think of it as fine-tuning your fuel strategy for a long race.

Strategic Carb Consumption: Here’s a tip – you can still stick to keto but make a small concession for your high-intensity training needs. How? By consuming about 20 to 30 grams of fast-digesting carbs, like fruit, about 30 to 60 minutes before your workout. This is like giving your muscles a quick fuel top-up right before they need to perform. It ensures they have enough glycogen to power through your training, especially during those intense parts of your workout.

The Balancing Act: This approach is all about balance – maintaining a state of ketosis most of the time, while also giving your body the carb boost it needs for specific high-intensity workouts. It’s like being a hybrid athlete, using both fat and carbs strategically to optimize your performance.

So, as you lace up your shoes and plan your nutrition strategy, remember that keto can be flexible. It’s about finding the right mix that keeps your engine running smoothly, no matter the distance or intensity of your runs.

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