EP004 What To Eat Before A Marathon: Here’s What You Need To Know

What to eat before a marathon event

What To Eat Before A Marathon

This week on The Smart Runner Podcast I’m taking a look what to eat before a marathon. It’s a question asked by marathon runners the world over and by the end of this episode, hopefully you’ll be a little wiser.

I’m looking at whether you should carb load, or whether you should not. If you’re going to carb load, I take a look at how you can do it. I look at what carbs are best in the days before your event and how much you should eat.

Links From The Show

  1. Paleo For Endurance Athletes
  2. Rich Roll Blog
  3. Rapid Carbohydrate Loading (UWA Method)
  4. What is lactic threshold?

Show Notes

In this episode Larry takes a look at;

  • Training to 18 or 20 miles is not enough
  • Testing different foods in training
  • Carbohydrate depletion
  • Managing your food on marathon day
  • Steering clear of fake foods
  • Running on empty is a good idea (in training)
  • If you think you need it, then you do
  • Keeping your diet clean

Carb loading in the run up to an event is the marathon fueling system of choice for pretty much all marathon runners. It’s an old school means for athletes to load up on essential calories needed for the 26.2 mile distance.

Carb loading done correctly usually allows athletes to store up to 1500 kcal of glycogen for women and 2000 kcal for men. Glycogen is mainly stored in the muscles and liver.

Depending on a couple of metrics such as your weight, sex, how long it takes you to get around the course, you could need almost 4000 calories to get through the marathon.

Check out this calories burned calculator to find out how much you’ll need to get you around then practice your food plan in training. Get your nutrition plan in place early, develop it, experiment with different foods and when you find what works stick to it.

Finding Your Threshold Before Race Day

Understanding the natural capacity of your own body to deliver the fuel you need for a marathon is very important. Your muscles and liver store glycogen and knowing at what point you run out of that fuel can help you plan much better.

Some sources make this process a complex undertaking, but here we’ll keep it simple.

Here’s what I’d suggest;

Get up early, drink water only and go for an 18 to 20 miler on an empty stomach. Eat normally in the days leading up to this run.

You’re looking to take your body to it’s limit here without additional fuelling and when you do, you’ll know what your body can deliver under normal circumstances (without carbohydrate loading).

Let’s say you run out of fuel at 15 miles, now you’ll know that you’ll need to refuel at 12 or 13 miles in future. You’ll know when you hit a wall because your legs may weaken and feel heavy, and you’ll feel drained.

It’s a good idea to pick a loop course close to home for this exercise 🙂

The following weekend, load up on complex carbs like whole grain rice, wholemeal bread and potatoes 2 days before your run. Now do the same route and at the same pace as before.

You should see a marked difference in your energy levels and how well your body performed over the same distance. You may even reach the full distance without additional fuel during the run.

Whatever happens, after performing this test you’ll have good knowledge of what your body can do when carbo loading and when not.

Choosing What To Eat Before A Marathon & Long Runs

When choosing what to eat before a marathon, it’s best for your health and performance to stick to real food. Keep your diet clean and free of preservatives, additives and fake food like gels and sport drinks.

Go for fresh fruit and vegetables, fresh lean meat, nuts, seeds in your day to day diet, and if you’re going to eat rice and grains then stick to whole food options in the days up to the event.

As I always suggest, test this stuff out yourself.

Whole Food Carbs For Carbo Loading

  • Whole grain and wild rice
  • White potato
  • Sweet potato
  • Oats

High Sugar Carbs On Marathon Day

  • Very ripe bananas
  • Apple and orange juice (squeezed fresh)
  • Honey & sea salt home made gels (I’ve not found a reliable source for homemade gels so I’ll experiment and report back in a later article)
  • Any other high glycemic foods like watermelon


Thanks for checking out The Smart Runner Podcast. If you liked this episode or you have something to add to the conversation, please let me know in the comments below. Please like or share on Facebook or post a review on iTunes too!

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