Runner’s Diet: The Complete Guide to Eating for Endurance

Eating right can not only make you feel overall better but can also help you run better too!

In fact, if you truly want to get better at running, there is no substitution for having the proper runner’s diet.

After a long break from marathon training, during the Pandemic I found myself prepping for the Chicago marathon, which turned in to training to run my first ever Ultramarathon…solo.

Building miles and getting refocused on a running diet was HUGE.

The diet you have as a runner can have a trickle down effect on the way you run and whether or not you’ll be able to beat that PR.

In this article, learn exactly what a runner’s diet is, why it’s important, and exactly what you should be eating as a runner.

What’s a Runner’s Diet?

Food is a source of energy, and energy is exactly what runners need. Eating healthy is one of the most important pieces of having the race day you want.

But eating healthy doesn’t mean removing entire food groups from your daily meal plan or restricting your calories.

What it actually means eating in a way that helps you feel good, boosts your energy levels, controls your mood, and enhances your overall health and fitness.

A runner’s diet is all about eating the right foods, at the right times so you have plenty of energy to fuel your runs and nutrients to improve recovery. Better recovery means being able to do the next workout. Pushing on hard days and not being so worn out you can’t do the next run.

A runner’s diet should have a healthy mix of the three macronutrients: carbohydrates, proteins, and fats.

People will generally consume adequate micronutrients if they focus on eating a variety of fruits and vegetables. These contain vitamins and minerals that aid the body’s function and recovery after exercise.

As for the macronutrients, there’s a lot of key information that you need to know and keep in mind to fuel your body right. And that’s exactly what we’ll be discussing in detail in this article.

What’s Important in a Running Diet Plan?

• Eating enough calories to maintain energy as the miles increase
• Not relying on sugars and quick carbs, but whole foods for fuel
• Focusing on eating enough protein to maintain muscle mass
• Including a wide range of nutrients to prevent runger
• Figuring out how to eat 5 servings of vegetables a day for maximum nutrients

And more importantly, remembering that a runners diet doesn’t mean restriction.

It means a style of eating that supports your goals!!

Who hasn’t spent the last mile of a long run fantasizing about a huge slice of cake, a burger or maybe for you it’s the sound of an ice cold coke fizzing in the can. There’s not a darn thing wrong with enjoying these foods because our body is reminding us that it needs fuel.

But obviously an entire day or week or month of eating these foods isn’t ideal for boosting our endurance training.

Eating healthy also doesn’t mean you can’t indulge a little here and there. It’s totally okay to indulge in an occasional treat, but make sure that the bulk of your dietary choices contain the essential vitamins and minerals your body needs for training.

Marathon Runners Diet

We have a tendency to focus on those treats and the idea of a high carb lifestyle as the way that marathon runners should eat, but nearly everyone will tell you that’s lead them to gain weight.

It seems impossible to be running more miles and gaining weight, but the wrong foods, the wrong fueling and the stress of the  miles makes it all too common.

Here’s what we’re going to cover:

• Importance of a runners diet plan to success in training
• Runners diet plan examples
• How much protein runners need
• How many carbs runners need
• How many calories do runners need (separate detailed article)
• How to fuel long runs with whole foods (separate detailed article)

Importance of Diet for Runners

If we looked at a pyramid of what matters most when it comes to our running performance a lot of people would be disappointed to realize that all the running supplements and recovery tools are near the top (meaning least important, but still useful once you nail down your nutrition).

This pyramid is a great way to put where you spend your time in perspective.

What we’ve all come to learn is that every body works differently in regards to fueling and race day nutrition.

But the one thing that all endurance athletes NEED GOOD QUALITY food the 75% of time they’re not training.

Food as Fuel for Runners

Food fuels our bodies, and the right kind of fuel can make all the difference. It’ll keep you running stronger and better as you clock miles. On the other hand, the wrong type of food may slow you down or cause digestive issues.

Let’s first understand exactly how food acts as a source of energy and fuel in our bodies. It will also allow you to make better choices when selecting what to include in your diet.

Muscle cells get their energy from two sources, namely sugar (carbs) and fat. This mainly comes from the food we eat or from within our own bodies.

The body breaks down carbohydrates to simple glucose, which is a form of sugar that circulates in the bloodstream and fuels your cells.

Glucose that is not immediately needed is stored in the muscles and liver as glycogen, another form of sugar. When you run, your body consumes sugar from your bloodstream first, then taps into stored glycogen when glucose levels drop.

Fat, which is another source of energy for your muscles, is used when you run easy or do other types of endurance exercises.

Dietary fat is less easily available than carbohydrates and less effective as fuel, especially during intense workouts. This is because it has to be broken down into fatty acids and other components first.

On the other hand, stored body fat is a great fuel source since everyone, even the leanest runner, has a lot of it. In fact, regular running improves your body’s ability to use fat as fuel, which is one of the best benefits of running.

EVERY SINGLE RUN uses both carbs and fat, the amount used changes based on intensity.

What Should Long-Distance Runners Eat?

The number of calories runners need depends a great deal on body size, speed and percentage of calories burned from carbs or fat.

I fully recommend working with someone to make those determinations, but you can use online calculators to get you started.

However, as I’ve stated previously with those calculators I’d be eating enough to gain weight, not maintain and definitely not lose body fat.

• You don’t want to have massive calorie deficits, which can lead to energy swings that make training harder
• You don’t want a high volume of calories from sugary processed foods which cause inflammation
• You do need to plan ahead for meals to eat enough quality foods

I do NOT like to share what I eat because there’s no guarantee it will work for you. But in Macros for Runners there is a sample day of eating from one runner and I will give you and idea of mine now.

In the following sections we’ll breakdown each component of during a workout, carbs and protein.

Marathon Runners Diet Plan Example

Following is a sample day from while I was running 50 miles per week, strength training 3 days and worked with someone to figure out how to keep my energy steady.

• Pre-run: 1/2 scoop protein powder with 12 oz water (usually some green juice), + 1 tbsp nut butter + 1/2 cup cheerios (I’m usually only awake for 30 minutes or so before I run, so I keep is small and fast)
• Breakfast: 1 slice Ezekiel bread, 2 oz avocado, 1 turkey hot dog, clementine and 1/2 scoop protein powder
• Snack: 1 slice Ezekiel cinnamon raisin bread, 2 tbsp nut butter, 1/2 apple
• Lunch: 4-5 oz chicken breast, 2 cups greens, 4 oz baked potato (usually a piece of dark chocolate too)
• Snack: 1 cup cheerios (I love cereal), 2 tbsp nut butter and often some jerky
• Dinner: 5 oz ground turkey, 4 oz sweet potato, asparagus
• Snack: 1/2 Perfect Bar

Not so much in to meat? Checkout this post on transitioning to be a plant based marathon runner.

You can definitely be a vegan runner, but you need to do the proper planning to not only hit your calorie goals, but the amount of protein needed to ensure you maintain muscle.

Especially for females who may have issues with low iron, which can cause a host of issues.

What is the Best Diet For Marathon Training?

As you can see above I tend to run something close to the Zone Diet and that works for my body (and those post menopause) and the way I train with Low Heart Rate burning more fat than carbs.

Some runners really like the high fat diet for endurance athletes, but I’ve found they have issues sticking to it long term and we now know that for women it can lead to hormonal imbalances.

• Long standing rules have said runners need 60% of their diet from carbs, but we’re seeing more and more that’s not true.
• One of the main issues is at that rate, few runners are getting it entirely from whole foods and instead are eating a lot more processed sugary treats.
• The best diet is one that leaves you feeling good, helps your body to repair quickly and prevents bonking from sugar crashes.

Main Building Blocks for a Runner’s Diet

Although our bodies require a wide variety of nutrients, the most important ones, referred to as macronutrients. These can be divided into three categories:

• Protein
• Carbohydrates
• Fat

Macronutrients, or macros for short, refer to a wide range of chemical compounds that our bodies require in large quantities for proper functioning. Micronutrients are the vitamins and minerals essential to function.

Having a balanced diet is one of the most important things for a runner. A balanced diet for runners should consist mostly of complex carbohydrates, moderate amounts of lean protein, and sufficient amounts of healthy fats.

Let’s look at what each of these macronutrients does in our bodies and how much you need to have according to your body.

Guide to Dietary Protein for Runners

Protein is considered to be the building block of life. And so, these compounds are required to produce energy, maintain basic biological processes, and sustain life.

Proteins are required for building, repairing, and maintaining cells, tissues, and organs throughout your body.

They are also necessary for other vital bodily functions such as metabolism, digestion, the generation of antibodies to combat infection, and so on.

When your glycogen stores are depleted, protein can also be used as a source of fuel. This is especially true during long hard training sessions and runs.

Complete vs Incomplete Protein

Protein is made up of 20 different kinds of amino acids, all of which are required for optimal functioning.

Only nine of these are considered essential amino acids. These are the compounds that our bodies require but do not produce themselves. You’ll have to get them from the food we eat.

• 20 amino acids
• 11 the body can produce
• 9 essential amino acids that must be acquired through food or supplementation
• 3 are considered branch chain amino acids
• leucine is the MOST important amino acid

For this reason, not all proteins are created equal. Some are complete, while others are not. Complete proteins have all nine necessary amino acids. As a result, your body can quickly utilize them for protein synthesis, which is the process through which muscle tissue is built or repaired.

Animal products are the primary suppliers of complete proteins. You can get all the essential amino acids your body needs from most animal-based forms of protein such as chicken and beef, as well as eggs and fish.

Incomplete proteins are those that have a good amount of amino acids, but not all of the nine essential amino acids, or don’t have enough of them to meet your body’s needs.

As a result, if you consume incomplete proteins, your body will not be able to fully use them during protein synthesis.

The majority of plant-based sources, such as vegetables, beans, grains, and nuts, are often lacking in one or more necessary amino acids.

The fact that incomplete proteins are incomplete does not imply that they are inferior. Nor does it imply that a plant-based diet cannot provide adequate complete proteins.

Simply combining different plant-based foods can assist in providing your body with the necessary balance and amount of essential amino acids.

Protein in a Runners Diet is Very Important

Eating higher protein helps maintain muscle mass when you’re in a calorie deficit, really important for endurance athletes who are almost always going to be low on calories after massive workouts.

And LADIES listen up that post workout 30 minute window is really important for you!!

Protein expert Stuart Phillips, PhD from McMaster Univeristy says runners need a minimum is 1.6 grams per kg of body weight per day (2.3-3.1 for muscle building).

• 1 gram per lb of body weight often works as easy math for women
• Eating enough protein helps manage the hunger from marathon training
• Eating enough protein helps keep hormones in check and prevent muscle loss
• Protein can absolutely be a combination of plant and meat sources
• Try not to rely just on protein powders, you want the full range of nutrients from food, plus it’s more filling

It’s also important to remember that you need to get in ENOUGH calories to prevent muscle wasting.

A consistent period of being in calorie deficit means your body will begin to use muscles, not fat, to provide the energy you need for those long workouts.

Read more on maintaining muscle mass with endurance training >>

Guide to Carbohydrate Needs for Runners

For the most part, consider carbs to be your body’s primary source of fuel.

When you eat carbs (except fiber), your body breaks them down and turns them into glycogen which is a form of glucose. It then stores this glycogen in your muscles, liver, and bloodstream. These stores serve as a source of energy for your body.

When you run, glycogen reserves are transformed into energy, which contracts the working muscles.

The more time and effort you put into your run, the more glycogen you use up. After a 90- to 120-minute workout or long run, most runners’ glycogen reserves are drained.

It’s important to note that when you eat more carbohydrates than you burn, the excess gets converted to fat and which is stored energy for use later. That is why eating too much of it causes weight gain.

Simple vs Complex Carbs

Not all carbs are the same, and the effect on your body also changes as a result of which type of carbohydrate you’re having. There are two types of cards: simple carbs and complex carbs.

It’s essential to understand the differences between the two forms of carbohydrates. Simple carbohydrates are found in everything from sugar to fruit, but complex carbohydrates, or starches, are found in whole grains and vegetables such as sweet potatoes.

Each form of carbohydrate raises blood sugar levels but in a different way. Simple carbohydrates, often known as sugars, are made up of shorter chains of molecules and digest faster than complex carbs.

Because of this, simple carbs cause a surge in blood glucose, providing the body with a short-term source of energy. The initial surge in energy is responsible for the so-called “sugar rush” that we all have heard of. AND is key to fueling during long runs or your marathon fueling strategy.

Do NOT fear simple carbs for your training.

What Type of Carbs Should Runners Consume?

Simple carbs and complex carbs are both necessary for runners to correctly fuel.

Simple carbs can be found in healthy meals like milk and whole fruits, which include a range of vitamins, minerals, and other nutrients. And of course in tons of processed foods like sugary drinks, candy, cookies and all the best energy gels for running.

Complex carbohydrates can also be found in unhealthy forms such as highly processed starches e.g., refined white flour that’s used to make white bread, pasta, etc. However, most are found in whole grains and vegetables such as sweet potatoes.

In general, complex carbohydrates are unprocessed and contain a variety of essential nutrients and fiber that are naturally found in food. Complex carbs also have a low to moderate calorie density, making them a key part of your daily diet to get enough nutrients.

This means you may eat enough to fill yourself up and satisfy your hunger without worrying about putting your entire nutrient balance and calorie intake out of balance.

How Many Carbohydrates in a Marathon Runners Diet?

Over 100 years of research back the idea that we need carbs to perform. More studies are showing that those on keto are not performing as well come race day, plus developing longer term health issues like low testosterone.

Our bodies need proper nutrients to fully recover from each workout and to work hard when we ask it to! Even if you’re doing LHR training and burning mostly fat, there’s a saying that “fat burns in a carbohydrate flame.”

YOU MUST EAT CARBS. They give you energy and are important for well rounded diet.

A good 4:1 ratio of Carbs and Protein after your workout is key to recovery.

Examples:

– Brown rice and eggs
– Turkey wrap
– Oatmeal and cottage cheese
– Cheese on GF toast
– Quinoa and chicken or pork bowl

The meals consumed after workouts should be protein/fat/vegetable based.

These are the “building blocks” of good nutrition, and your body will naturally crave them if you fueled properly before. And remember this isn’t about perfection or being a zealot about your food!

When you’re too low in carbs, your sugar cravings will increase and you’ll feel fatigued in training. You may also find you have trouble sleeping! Your body is stressed and struggling to recover. And you aren’t feeding it what it needs.

Checkout more post run meal ideas >>

Guide to Healthy Fats for Runners

Dietary fats, like carbs and proteins, are an essential macronutrient that your body needs to function properly.

Fats are important in our body to transport fat-soluble vitamins such as A, D, E, and K throughout your body and help improve nutrient absorption. It also helps keep the immune system strong while ensuring proper functioning at the cellular level.

Fats are also what helps aid in hormone production, mainly testosterone and estrogen. It helps also control inflammation and blood clotting.

Most importantly, fats are a secondary source of energy for your body and are the largest reserve or stored fuel.

Saturated vs Unsaturated Fats

There are two types of dietary fats based on the impact they have on the body. They’re called saturated and unsaturated fats.

Unsaturated fats are often referred to as the ‘good’ fats. These are the ones that help fight diseases and include antioxidants that prevent illnesses. In fact, unsaturated fats can lower harmful cholesterol levels, lowering your risk of cardiovascular disease.

Some sources of these ‘good’ fats include olive oil, avocados, nuts, seeds, fatty fish, and peanut butter. Runners MUST include these in their diet.

Saturated fats, on the other hand, are known as the ‘bad’ fat and can block your arteries. They contribute little to your overall health and should be avoided.

These fatty acids raise total blood cholesterol and LDL (low-density lipoprotein) cholesterol levels, increasing the risk of heart disease.

Saturated fats are found in animal-based products including red meat, poultry, and full-fat dairy products. Doctors recommend to limiting them to no more than 7% of your total calorie intake.

Tips for a Healthy Runners Diet

Sometimes life happens. We’re stuck without proper food because we’re traveling or at the mercy of a work conference filled with pastries and a lunch wrap of iceberg lettuce.

But a marathon runners diet is in fact part of their training!

If you can nail your nutrition 80% of time, then that’s great!

The other 20% of the time, do whatcha can, don’t freak out about it. Sometimes that stress just causes more damage.

• Remember that high quality pre-workout snacks and POST run meals mean you won’t need to take in as many quick carbs like gels during the run.
• Pack snacks to take with you that don’t need to be in the fridge like an apple, jerky, nut butter packets, roasted chickpeas, protein powder
• Think about meals being a BALANCE of both protein and carbs, this will keep you from getting that raving hunger just a short bit after eating.
• Actually eat enough at your meals so that you don’t need to just rely on snacks, which often aren’t as high quality food.
• Decide you’re going to commit to meal prep because your goal matters
• Change your thoughts around food from restriction to eating for performance
• Focus on NUTRIENTS and you’ll find your food falls in to place more easily
• Hydrate like it’s your job…cause it kinda is.
• Don’t worry a great deal about variety, if you’ve found a way of eating that’s allowing you to eat enough and high quality, stick with it. This also helps reduce hunger interestingly.

Thanks to my friend Lindsay Cotter, a blogger and Nutrition Specialist over at Cotter Crunch for contributing a lot of great information to this article, she has worked with many amazing Sports Nutritionists, and endurance athletes, including her own husband who raced professionally for years!

Hope you found these tips somewhat useful in creating your own optimized marathon training nutrition!

Still looking for more information?

Checkout these additional articles on a healthy runners diet:

• Sports nutrition for runners
• Running for weight loss guide
• Avoiding common running nutrition mistakes
• How to fuel long runs with whole foods
• How to fuel during a marathon

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