Carbohydrates and Long Runs

How many carbohydrates do you need to consume while running

I’ve talked about the importance of hydrating during training, but something equally as important is fueling up on carbohydrates. 

I’ve made the mistake of not fueling up enough during a long run and my run suffered from it. I become tired, irritable, and just plain slow.

Like hydrating, not all runs require additional carbohydrate intake.

On average, it is not necessary to consume additional carbohydrates if you are running for less than 60-90 minutes. Why such a range? For me it really depends on time of the day and what I ate the night before. I run early in the morning, so if I am running 90 minutes or less I don’t need additional carbohydrates. However, if I am running later in the day and haven’t snacked for a while, I may need some form of carbohydrate intake for a 60-90 minute run.

Others may find that after 60 minutes they need some additional carbohydrate intake. That is just something you’ll have to figure out for yourself, and find what best works for you.

Extra Fuel While Running

After 60-90 minutes of running our bodies tend to use up our carbohydrate stores as fuel, and then rely on our fat stores. It sounds great that we are burning off fat, but without glycogen in our system our bodies can become fatigued and it is possible to feel faint. That is why it is important to replenish our carbohydrate stores while running.

Amount of Carbs

The amount of carbohydrates you need really depends on your body weight. These formulas show the high end and low end of carbohydrate intake.


Body weight in kilograms
(BW in pounds/2.2) X 0.7 = grams of carbohydrates per hour

Body weight in kilograms
(BW in pounds/2.2) X 1.0 = grams of carbohydrates per hour

I should take in approximately 40 to 57 grams of carbohydrates per hour, depending on my pace and race distance. For example, for a half-marathon I would take in a lower intake of carbohydrates, closer to 40 grams. For a full marathon I would take in more .

Carb Intake

For all of my past races I have used GU. GU has about 20-25 grams of carbohydrates per much. That is not the recommended 40-57 grams that I need per hour. However, with GU I usually have one pouch for every 45-50 minutes I am running. I am also consuming energy drinks while I go on long runs, which can also have carbohydrates in them. I personally love the Vanilla Bean flavor!

At most major marathons there will be an abundance of energy gel/candy/fruit stations to give you multiple opportunities to fill up on more carbs.

Some other forms of carbohydrate intake are:

  • Berries
  • Bananas
  • Energy bars
  • Sports drinks
  • Medjool Dates (love!)
  • Energy gels

Once you find what form of carbohydrate intake you like, you will also have to figure out the ratio of carb intake/per hour that works best for you. What works best for me may be completely different than what works for you.

For my first marathon I consume something at every station whether it was energy gels, candy, fruit, or sports drinks. I learned that consuming too much caused discomfort in my stomach. I’ve learned what works best for me is consuming an energy gel approximately every 45-60 minutes, mixed with drinking.

I would suggest figuring this out during your long runs, so by the time race day comes around you are comfortable with who you will refuel. You never want to try anything new during a race.

And of course, if you have questions just leave a comment.

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