5 Nutrition Tips for Marathon Runners

Running your first or 20th marathon? These nutrition tips for during the marathon can help you prepare for your 26.2 mile race and improve your nutrition strategy.

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Whether you’re planning to run your first marathon or 15th marathon, there are some nutrition standards you’ll want to follow.

Nutrition tips for new runners and seasoned runners are one in the same. Although, once you’ve been running for enough time, they will become second nature to you.

While having a running coach or plan is helpful and even a necessity for some, understanding your nutrition while training for a marathon is just as important. I would even argue that it’s more important.

Eating enough quality foods, knowing what to eat before a long run, understanding nutrient timing and how to fuel your body will enhance performance, reduce your risk for injury, help you recover faster and more efficiently, and balance your hormones better.

1. Understand the Importance of Carbohydrates

To understand the nutritional requirements for marathon runners, you first have to understand the function of carbohydrates in a marathon training diet plan or long distance runners diet plan

Carbohydrates are the primary, quick energy fuel source for your body and for exercise. Essentially, they are strands of glucose linked together.

Depending on how long the strand is, carbohydrates can be considered simple (shorter strands of glucose) or complex (longer strands). Both have a purpose for running and endurance athletes, so low carb running often won’t get you the performance you’re seeking. 

When we eat carbohydrates, our bodies can use them quickly for energy. This is why a pre-run meal or snack is typically high in carbohydrates. If not used initially, our body can also store carbohydrates as glycogen to use at a later time. 

Whether you’re training for a half marathon, marathon or even ultramarathon, carbohydrates are going to be your friend. A vegan long distance runner will just want to avoid animal sources, such as honey, whey, or gelatin and look at ingredients in sports fuels. 

Skeleton with muscle groups shown

For example, as you start running, your body will use any instant carbohydrates (glucose) it has available. Then, it will pull energy from your glycogen stores in your liver and muscles. Pretty neat!

The body is very efficient at converting this glycogen to glucose to enable the muscles to contract and help us run.

As we enter the middle portion of a marathon and beyond, your body is starting to run out of glycogen stores, which is why it becomes extra important to replenish glucose on a consistent basis.

Research has shown that carb loading before a marathon or long race can improve performance by 2-3%! A good way to do that is through pasta dishes, since pasta is very carb-rich. Here’s more about pasta for runners

2. Nutrient Timing

Nutrient timing is a planned intake or manipulation of macronutrients. In other words, eating certain foods and food groups at strategic times in and around workouts to achieve better performance and outcomes.

You can use nutrient timing for muscle gain, better efficiency, muscle recovery, glycogen synthesis, preventing muscle breakdown and more.

Some examples of nutrient timing include:

  • Spreading protein intake throughout the day
  • Including caffeine as an ergogenic aid before a run (coffee vs pre workout)
  • Planning your hydration before a run
  • Carb loading days/week before your race
  • Combining carbohydrates and protein in a post run meal or snack within a couple hours
  • Including leucine rich foods in your post run meal
  • Including a protein-rich snack before bed
  • Pairing iron-rich foods with Vitamin-C rich foods, especially if you follow a vegan or vegetarian diet
  • Separating high calcium foods from high iron foods (as they can inhibit absorption)

And much more. I will write a more in depth post on this soon.

3. Eat Enough

The amount of food and calories necessary to sustain marathon training will vary from person to person. In many athletes, it will be upwards of 2500-3000 calories/day.

Rather than relying on calories, though, I always advise my athletes to tune into signs from their bodies.

Becoming aware of some of the signs of undereating can also help you learn whether you are or are not eating enough for your body.

Tuning in to Hunger – I can not stress how important it is to eat when you feel hungry. Proper nutrition for marathon training requires eating substantial amounts of food to help your body recover from long and hard runs and workouts.

brown rice, veggies and meat in meal prep containers

The more running you do, it’s safe to assume the more food you need to eat. Think of food as energy and that’s what will help you perform and recover your best.

Hunger is an ask from your body. Rather than ignoring it, listen to it and honor it.

Hunger is an ask from your body. Rather than ignoring it, listen to it and honor it.

Trouble Sleeping – Trouble sleeping can be a sign of overtraining and/or undereating so it’s important to take this into context with some of the other signs that may be present.

Practicing good sleep hygiene is a great thing to do regardless. Things like including blue light blocking glasses when looking at phones, screens or tv’s, doing some journaling or meditation before bed, sticking to a consistent sleep and wake schedule and only using the bed for sex and sleep are great places to start to initiate a solid sleep routine.

The Nail Your Nutrition podcast also has a whole episode with sleep researcher, Amy Bender, for more great tips on the benefits of sleep for athletes.

silver alarm clock on night stand with person sleeping behind

Loss of Menstruation – For those who identify as women, the loss of menstruation can indicate the body is in an energy deficient state. Think of it this way: menstruation is not an essential function for the body to work. It is very important but the body puts it on hold to prioritize other things when energy is low.

Things like the heart beating, lungs pumping oxygen, making red blood cells and more. Therefore, a sudden loss of inconsistent menstrual cycles may warrant further inspection.

Altered Lab Work – How are iron stores? Iron stores can be low in runners, especially women. This is something to consult with your doctor and/or Registered Dietitian about.

Altered Mood and Cognition – You may not initially attribute an altered mood or mood swings to undereating, but it is definitely a symptom. As discussed in this paper on Relative Energy Deficiency in Sport, there is a huge psychological part that comes into play with undereating.

Whether it’s brain fog, decreased concentration, altered cognition, depression, and/or mood swings, these things can be symptoms of overtraining, undereating or both. This would be another thing to take into context with other symptoms and lifestyle factors.

4. Stay Hydrated

Obviously, staying hydrated is important for overall health, but it’s also going to help with your training.

Understanding the importance of hydration for running and electrolyte balance is critical.

While you don’t need to know all of the in’s and out’s, knowing how much to take in will help you, especially for your half marathon hydration plan.

We have a whole module on hydration and electrolytes in the Nail Your Nutrition course.

Knowing your sweat rate, how much to take in before, during and after a run, and how to incorporate electrolytes into your training plan will help you succeed.

Hydration strategies for the marathon can be complicated but important to avoid hyponatremia or hypernatremia.

There are devastating consequences to both under- and over-hydrating.

Girl dehydrated leaning against tree with water pack on

Your hydration and nutrition plan for a marathon should be practiced religiously in long runs and top of mind during regular runs, too. Having a hydration pack or hydration belt is a great bet to ensuring you stay hydrated.

Some of my favorite hydration and electrolyte mixes include:

5. Practice, Practice and Practice More

Don’t take the idea of practicing your nutrition plan for your marathon for granted. It’s so important to practice it several times, several weeks or months before hand.

Why is this important? The gut is trainable. Training your gut just takes time and practice, and perhaps understanding what is aggravating your symptoms in the first place.

For example, not going into a run dehydrated and trying different sources of carbohydrates (glucose, fructose) and forms of carbohydrates (gels, energy chews, blocks, all-in-one liquids, real food) can make a big difference.

Also, understanding that a faster pace and heat can aggravate symptoms as well, so taking all of that into consideration. Minimizing fiber before a long run or race, or even trying a modified low fod-map diet may all be helpful things.

Knowledge is power, and this is where working 1-1 with a professional can be super helpful. in a hether

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