Sports Nutrition
for the Ultramarathon


Sports nutrition for the ultramarathon – meaning how you fuel your body before the race and during the race – is the next most important thing for ultra runners after their running training program.  By race day it is the single thing that will help you get your best performance.  If you don’t make the right nutritional choices, it can lead to suffering during the race and possibly not finishing the race.

Everybody is different and so each runner must decide what works.  And the best way to figure this out is by trying it out during your training program.  Only you can decide which foods and fluids your body can handle and the ones you prefer.

The guidelines on this page can help you understand sports nutrition requirements for the few days before the race and also during the race.  It will be up to you to try out the different suggestions during you training program to know what works for you.

Sports Nutrition – Pre-Race

There are two things going on prior to your ultra-marathon event:  you should be tapering your training for 1-3 weeks prior to the event, and for about 3-4 days before the event you should be doing carbohydrate loading.  The purpose of these techniques is to boost the glycogen stored in your muscles and liver so that they are fully topped up.  This gives you additional energy during the ultra event so that you will perform better.  It’s been estimated that the improvement can be as much as fifteen minutes for a marathon event, so for an ultramarathon it would likely result in even greater improvements.

During your training phase carbohydrates are probably about 60-70% of your diet.  During the carbohydrate loading phase you will want to increase this to around 70-80%.  (See carbohydrate loading page for more details.)

If this percentage is too vague for you, then you can also estimate your carbohydrate intake as about 8-10 grams of carbohydrate per kilogram of body weight per day.

Sports Nutrition – Day of Race:  Solid Foods

The purpose of eating solid foods during an ultra event is to keep your blood glucose levels in the normal range.  You need to start eating early in the race to achieve this, and you need to keep eating throughout the race.  And you should eat before you get hungry.  By the time you get hungry, your glucose levels have already dropped.

So remember the glycogen you stored in your muscles and liver before the race even started?  You want to conserve these stores, so in order to do this you want to start taking in carbohydrates immediately once the race begins.  You can do this with a mix of solids and liquids, so lets looks at the solid foods first.

Typical carbohydrate-rich foods will include fresh fruits and dried fruits, cookies, candy, energy bars, sandwiches, potatoes, vegetables, bagels and similar foods.  These are the foods you should be experimenting with during training and choosing the ones you enjoy eating and that don’t upset your stomach while you continue to run.  You don’t want to try anything new or different on the day of the race – so make sure you know what works for you prior to the event.

An average runner should consume approximately 1-1.5 grams of carbohydrates per kilogram of bodyweight per hour.  About half of this should be from solid foods, the rest should be from sports drinks and gels.

Sports Nutrition – Day of Race:  Liquids

You need to start the race well hydrated so the first thing you will want to do is drink 2-3 8 oz. glasses of fluids before the start of the race. 

During the race you’ll be losing fluids and so you should plan to drink 30-60 oz. (1 liter) of liquid every hour.  This is quite a large range, mainly because everyone is different.  Women generally need less fluids than men because they are smaller and may not sweat as much.   Also, the weather on the day of the race will play a big part in the fluids you need.  Hot humid weather demands greater quantities of fluid;  moderate, cool temperatures less.  The pace you are running also has a big impact.

Having a support crew is vital during an ultra-marathon because you cannot carry this amount of fluid with you.  Obviously, you will have done careful planning of the course and where your support crew will be needed to supplement aid stations along the way. 

It’s important to monitor your fluids to be sure you’re getting enough into your system.  If your urine is clear colored then you are getting enough fluids – if it’s dark colored then you’re not -- and you need to start drinking more fluids immediately.  Most people can drink a liter of fluid per hour so this is a good target to reach for if you’re unsure about how to plan.

Sports drinks or any fluids you are ingesting can cause you problems if they have too much sugar.  You want these to flow through your system easily and rapidly so make sure the concentration of sugar is less than ten percent.  You can dilute drinks with water in order to achieve this.

Also to take into consideration is sodium levels.  Runners who take in too much water and/or sweat a lot run the risk of hypoatremia.  Other runners at risk for this condition include the less fit and also people who tend to gain weight over the course of the event.  Women also seem to be more at risk than men because of lower body mass indexes. 

Hypoatremia is a condition where there is not enough salt (sodium) in your blood.  It occurs in about five percent of the runners in an ultra event.  It’s a serious condition and is potentially fatal so everyone should be aware of it and take precautions in planning their foods and drinks for the event.

Although there aren’t many definitive guidelines, make sure you know what’s in your foods, sports drinks and gels and especially pay attention to sodium content.  It’s believed that 200-500 milligrams of sodium per hour will prevent this condition.

Sports Nutrition Summary

So that wraps it up for the important sports nutrition considerations for ultramarathon runners.  Make sure that you are experimenting with foods and drinks throughout your training program.   Remember that you don’t want to try anything new or different on the day of the race.  By paying attention to the right sports nutrition for your event you will most likely feel better throughout the race and you will perform to your potential.

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