Carbohydrates - Why They are Vital for Runners

Carbohydrates are sugars and starches that the body utilizes for energy. They are extremely necessary to sustain energy levels in your body so that you can not only feel better while running but also help you go the distance in terms of marathon running. They are one of the most critical things that you need as a runner! Skip to the bottom of this page to see why. 

There are two main types of "carbs": simple and complex.

Simple carbs are an instant energy source. Most are high calorie foods such as processed/refined sugars and foods.

Examples: chips, sugary cereals, candy bars, ice cream

Yes, these are most of the tastier foods that we love to eat! They provide “quick energy” but it doesn’t last long. That being the case we should try to limit our intake of these. 

Complex carbs are typically lower in fat and calories and have higher amounts of fiber. They give the body greater amounts of energy that last for longer periods of time.


  • fruits
  • vegetables such as broccoli, peas and beans
  • whole grains
  • rice - choose brown rice
  • pasta - particularly whole wheat

You could probably guess that the healthier foods contain the “good carbs”.

The Importance of Carbohydrates in Endurance and Marathon Running

Don’t skimp on this nutrient especially the complex carbs when you are training for a marathon. Many people in the health field tell us to avoid eating carbs in order to lose weight, increase energy, so on and so far. However when you are logging many miles and expending large amounts of energy as in running long distances (or even short!), your body primarily NEEDS carbs!

When you run, the body uses carbs and fat as it's fuel source.

Here's what happens when you eat carbs:

  1. They are converted into glycogen - to be technical: a polysaccharide which forms glucose
  2. They are then transported to the muscles and the liver where they will be stored.
  3. When you exercise you burn those carbs as they give you your energy.
  4. If you do not exercise they will eventually be converted into fat - hence the weight loss experts advising us to avoid carbohydrates.

The more intense your run or workout is, the more you will burn carbohydrates. However at the same time you will be burning a percentage of your fat stores. When you go out on a long run, your body needs to have large stores of carbss in order to go the distance. If your body is depleted of carbs, you will not be able to go far.  (This carb depeletion is referred to has "hitting the wall" or "crashing", "bonking".)

Therefore, you can NOT be an endurance or marathon runner and eat a low carbohydrate diet.

So eat carbs, the complex carbs. Whole wheat, vegetables, fruit, healthy breads, pastas, and cereals. When you have a long run or race scheduled, eat more of them in order to increase your storage levels. (This is called carbo loading. ) If you are running over an hour at a time then take some kind of carbohydrate whether in the form of food or drink. Supplementing during your runs of 1 hour or longer has been proven time and again to improve endurance performance.  (See the energy drink guidelines and are you on the GU gel bandwagon?)

And the next time you are offered that delicious looking bread or a slice of chocolate cake, indulge. You've earned it, and as a runner you will burn it. That is the beauty of running. 


But if you want to really learn how to eat like a successful runner then you need the Eat Like a Runner Nutrition Course!

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