How Do You Properly Fuel For The Marathon?

Audio Transcript

Claire: Today’s question is from Coco and it’s about fueling during long runs and during the marathon.

Coco: Hello, my name is Coco and I have a question regarding fueling.

My question is, how much do I need to fuel during a long run, during the race and how often? Does it depend on my body weight because I’m pretty petite?

Usually after I take two to go, I don’t feel like having more sweets and things. I wonder if there’s another alternative fueling food that I can have.

Another question is, if during the long run, I feel gel distress early on in the race, and do I need to keep fueling as I always plan or I should stop until I feel better? Thank you.

Claire: Thanks for your question Coco. I’m going to go over a little bit about the science of marathon nutrition first, and then answer your question specifically.

Fueling during a marathon is extremely important to nail down just right, and there’s no one right answer for everyone.

The first thing to remember is that you need to experiment and figure out what’s good for you. No two athletes are the same and it seems that everybody reacts to things a little bit differently.

Nutrition is what separates the marathon from any other distance.

For any race or run that’s shorter than 90 minutes, your body generally will not run out of stored glycogen to burn, so fueling is less of an issue in shorter races.

Now you’ll probably feel better and perform better in any distance longer than about 45 to 60 minutes with some fuel during the run.

This is not because your body has run out of fuel; it needs more.

As soon as you take on fuel and the carbohydrate hits your mouth, signals are sent to your brain that there’s plenty of fuel coming and there’s no reason for you to panic.

This prevents your brain from going into its survival mode and allows you to keep up your pace.

There’s not enough time for a gel or whatever carbohydrate you’re using, during your 10k to get digested and be used for fuel, but your brain gets satisfied as soon as it enters your mouth.

It can be useful to take some fuel during a shorter race. For long runs and races beyond 90 minutes however, fuel becomes critical.

As you suspected Coco, your fuel needs, being a smaller woman, will be different from that of a larger runner.

You might, for example, need only 45 grams of carbohydrates per hour, while a bigger runner might need as much 90 grams.

If you have a sensitive stomach, you’ll probably want to take the least effective dose, but without knowing exactly how much you weigh, I can’t tell you how much you’re going to need.

At Runners Connect, we have some formulas that you can work that out, if you’d like.

The good thing is just like the muscles, the stomach can be trained as well, so we want you practicing your fueling plan during all of your long runs, so that you can really get it nailed down.

Let’s take a look at the fueling process and what actually happens.

Your body uses two primary sources of fuel to feed the muscles when you’re running and that’s fat and carbohydrates.

That is a pretty abundant resource and even the skinniest runner has plenty of fat for fuel, but fat is broken down into usable energy pretty slowly.

It makes it an ineffective fuel source when running anything faster than about marathon pace. Therefore, your body relies mainly on carbohydrates as its primary fuel source when racing.

Here’s the deal with that.

The faster you run, the greater percentage of fuel will come from carbohydrates, but the problem with carbohydrates is that unlike fat, we can only store a limited amount in our muscles.

Even when you do the perfect marathon tapper, you still have a finite amount of carbohydrates storage in the muscles and in the liver.

Typically, most people can store about 90 minutes of muscle glycogen when running at half marathon pace, and maybe about two hours when running at marathon pace.

Unless you can run a marathon in about two hours and so far no one has been able to do that quite yet, you will be running at a muscle glycogen long before you cross the finish line.

The solution, of course, is to take a gel or take some carbohydrates, but unfortunately those carbs that you ingest while you’re running are not a wonder one replacement.

The glycogen that you ingest while you’re running doesn’t always make its way to the working muscles, where you need it.

The reason why, is because carbohydrates are stored in both the liver and the muscles and your performance on race day relies on using the glycogen stored in the muscles.

In order for the glycogen to get to the muscles, it first needs to be digested, go through the intestines and then be absorbed by the muscles.

Obviously, this takes a lot of time and isn’t super-efficient.

You want to be proactive and you want to take the fuel well before you actually need it. When you are running hard like during a race, your body will divert the blood away from your stomach and your digestive system, to give your legs more blood and more oxygen.

In order to do that sometimes your stomach completely shuts down and that’s when you start getting the tummy troubles when you take a gel.

If you haven’t taken any gels until late in the race then you decide, oh goodness I’ve got to take a gel, I’m going to bunk or I’m getting close and you go ahead and take the gel, by the time your stomach has already essentially turned itself off, you’re going to have some serious issues keeping that down.

You want to begin taking your fuel relatively early in the race and that should be when your body is not under such great stress, and you have a better chance of processing the carbohydrate that you’re ingesting, and you hopefully won’t have any stomach issues.

A good rule of thumb is to fuel every 45 minutes or so, but again this is highly individual.

If you have stomach issues, you might want to consider stretching that out, pushing it back to maybe 60 minutes, so you’re not putting so much in your stomach.

To answer the second part of your question Coco, yes you still need to try to get in fuel even when you’re not feeling that great. I know it’s hard but there are a couple of tips that can help you get that fuel in.

One tip is to try eating a small portion of the gel but in closer intervals. For example, open your gel and eat a quarter of it every 20 minutes, instead of the entire dose at 60 minutes.

You’ll still get the energy that you need, but you’ll give your stomach a better chance of properly digesting it without getting sick.

Don’t forget to always take your gels with water. Don’t take them alone and never take them with Gatorade or some other kind of sports drink that has sugar in it.

Without water, energy gels take a lot longer to digest and enter the blood stream. If you take a gel with a sports drink, you’re running the risk of ingesting too much simple sugar all at once, and that will hurt your tummy.

To get back to the part of your question about not being able to handle too much sweet, it sounds like you haven’t found the right product for you.

There is no rule that you must take sweet gels to do well in the marathon.

There are lots of flavors out there, and you’ll want to experiment and see which fuel source works right for you. Something that you’d like and enjoy.

There’s also no reason that you have to take your carbohydrate in the form of sugar. It’s turning out that starches work really well, and they don’t have to be as sweet.

A very popular starch based product is called UCAN and many athletes have great success using that instead of the sugar based gels or maltodextrin based gels.

I personally have created a starch fuel using regular old corn starch that I mixed with some electrolytes, and salt with water and lemon, and it was very easy for me to take during the marathon.

I had no stomach issues and I probably will never go back to gels again because it works so well.

If you’re interested in the recipe on that, I have that on my blog at the plantedrunner.com so you can check that out and see if it’s right for you.

The most important thing to learn here is to experiment. See what’s right for you, and practice, practice, practice some more.

Don’t do anything new on race day but every time you do a long run, get out there, practice your nutrition, and make sure that it’s something that works for your tummy.

Be confident on race day.

Thanks for sending in your question, Coco.

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