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Fuelling advice for your best marathon ever

By Jörn Utermann (AthlEAT Coach)

Nutrition is like an extra discipline of endurance sport. It can help you perform at your best, but if things are not done correctly, your food and fluid intake might also be the reason why you don’t finish the race.

In other words, if you want to run your best marathon, then you need to know what to eat before and during the race.

What and when to eat prior to the marathon

The right dietary choices actually don’t start right before the marathon, but in the days leading up to the race (at least when you are a more serious runner). Usually, athletes reduce their training volume and intensity in the last days before a marathon. This is referred to as a taper and ensures your body is fully recovered when you go to the start line.

What if I told you, that there are nutritional strategies which will help you to maximise your energy stores and performance on race day?

Researchers have found that when well-trained endurance athletes increase their carb intake by ~25 % at the same time, this will result in a glycogen supercompensation – meaning the muscle will store more glycogen than it normally does.

This results in a more sufficient energy supply during the race. You also get away with consuming slightly less carbs during the race itself.

If you consider yourself to be more of a beginner, and simply want to finish the race, there is no need to consume that large amounts of carbs. Simply make sure to eat 3-4 meals a day that contain at least 2 portions of carbs, whereas 1 portion = 1 hand full of the following foods:

High-fibre carbohydrate sources. Source: Senpro
High-fibre carb sources. Source: Senpro

Low-fibre carbohydrate sources. Source: Senpro
Low-fibre carb sources. Source: Senpro

Do you have to eat high carb?

Research has consistently shown that high carb diets are superior to low-carb diets when it comes to endurance performance.

While there is a place to eat periodical low-carb during training to maximise the adaptations of the fat metabolism, all well-trained athletes fuel up on carbs for a competition.

Hence, if your aim is maximal performance, you should prioritize carbs before and during the marathon.

Pre-race meal

The main goal of the meal prior to a marathon (oftentimes breakfast) is to top-up your carbohydrates stores without putting much stress on your digestive system.

This means you should avoid larger amounts of dietary fat such as nuts, seeds, eggs, bacon, avocado or cooking oil. The same applies for foods rich in fibre such as vegetables, whole grains and legumes.

All these foods take a long time to fully digest and increase the risk, that you end up starting the race with digestive issues.

What should you eat then?

If your pre-race meal is breakfast (start time between 9am to 12pm), then having cereals (no nuts & seeds), bread or bagel with low-fat toppings, pancakes or French-toast and a smoothie are all viable options.

If your start time is in the afternoon, you could have a rice/couscous bowl with chicken and some low-fat sauce/dip, a wrap with some rice, or simply a pasta dish with tomato sauce (no high fat minced beef or pesto).

A full meal should be consumed about 3 hours before the start of the marathon. You could also eat a larger meal earlier and use a small snack with easy digestible carbs as a top up 60-90 min before the race.

Most importantly: make sure you have tested your pre-race meal and that you are positive that you are going to tolerate it well.

Pre-marathon meal options
Pre-marathon meal options

Food/energy consumption during the race

Even when your glycogen stores are completely full, they will only last for about 90 min of medium to intense exercise. Once your glycogen stores are empty, your body is forced to use more fatty acids to produce energy.

This usually results in a significant drop in performance because the conversion of fatty acids to ATP (universal energy currency of the body) is significantly less effective when comparing the conversation of carbohydrates to ATP.

“Hitting the wall refers to a state where you glycogen stores are depleted and your body isn’t able to utilize energy quickly enough to meet the demands of running a marathon”

Your priority should be to consume simple carbs that are easily digested and provide you with quick energy.

The best options are to consume sports drinks with some gels/some fruits like banana and orange/cola. A handful of salty crackers or mini-pretzels are also a viable option.

How many carbs you should consume mainly depends on the expected duration. The longer you are running, the more carbs you need per hour to avoid hypoglycaemia (drop in blood glucose levels) and depleted muscle glycogen stores (results in acute performance drop).

Carbohydrate Intake during exercise. (Jeukendrup, 2014)
Carbohydrate Intake during exercise. (Jeukendrup, 2014)

The amounts mentioned in table X give you a good overview of the carbs you should aim for if your goals is to maximize your running performance.

However, note any intake larger than 45g per hour should be practiced during training as it can result in serious stomach upsets. Also, you can only absorb 60g of glucose per hour in your small intestine. If you consume more than that, you have to use sports nutrition products that contain fructose as well. This is a different type of sugar, that is being absorbed via a different carrier protein and hence allows you to increase your carb intake while mitigating the risk of stomach cramps.

Most gels, but not all sport drinks, contain both glucose and fructose. The ideal ratio is between 1 to 0.5 glucose:fructose to 1 to 0.8 glucose:fructose. So make sure to study the label closely, if you aim for a higher carb intake.

What about fluid intake?

The most important aspect of managing your fluid intake is that you start your race in a well hydrated state! If your body is already slightly dehydrated before even starting the run, it will be very challenging to avoid dehydration levels that will impair you performance and eventually make you feel dizzy.

So how do you know that you’re hydrated, you might ask yourself?

Good question, as you don’t have the expensive measurement tools at hand that scientist use.

Fortunately, there is an easy yet accurate protocol that you can use:

  • Drink 5-7 ml per kg body weight 2 to 3 hours before the start of the race (for an 80 kg athlete this would mean 400-500 ml)

  • This should be enough fluid to make sure you are well hydrated and gives you enough time to use the toilet to get rid of extra water your body isn’t using

  • Make sure to check your urine colour when you use the bathroom

  • If the colour of your urine isn’t clear, then drink an additional 250 ml.

Water intake during the race

Telling someone exactly how much they should drink during a long endurance event is a bit tricky.


Because the amount of fluid that athletes lose via sweat, and should therefore replace, varies greatly between athletes.

Effects on sweat rate include:

  • Genetics

  • Body-size

  • Temperature

  • Humidity

  • Clothing.

An average sweat rate for endurance activities in the late summer is between 1-1.5 L per hour. To avoid dehydration levels greater than 2% of your body-weight (that’s when you performance will start to decline), you should try to consume 750ml to 1l per hour. Athletes with higher sweat rate should aim for the upper end of the range.

Ideally you would break this up into multiple smaller sips to avoid too much water being pushed around in the stomach, which may upset your stomach.

What about electrolytes and sport drinks?

It is true that athletes lose electrolytes in their sweat. But only one electrolyte is lost in large amounts and directly affects performance and well-being during exercise.

And that electrolyte is sodium.

The condition when sodium concentrations in the blood reach critically low levels is referred to as hyponatremia. Because of the low sodium, the amount of water in your body rises and causes your cells to swell which can cause serious health concerns. Proper sodium also helps to maintain adequate fluid in the cell and keep you hydrated.

Sport drinks are simply the most convenient way to consume fluid and electrolytes together with carbs: the three most important nutrients for your performance. A good sport drink contains about 700 to 1000 mg of Sodium/L.

Additionally, it is also known that fluid carb intake causes less gastro-intestinal upsets, when compared to consuming them in solid form.

By Jörn Utermann (AthlEAT Coach)

About Jörn (Jay) Utermann:

Jay is himself a passionate athlete, with vast sporting experiences including handball, tennis, martial arts and CrossFit. These diverse experiences allow him to truly understand the needs of athletes.

To improve his knowledge and coaching skills, he is constantly analysing relevant science journals and exchanging ideas with other experts.

Jay's educational background:

• MSc in Sport and Exercise Nutrition, Leeds Becket University (UK) • IOC Diploma in Sports Nutrition, International Olympic Committee • Bachelor in Nutritional Science, HAW Hamburg.

Interested in professionalizing your nutrition, so that you can exceed your potential? Then get in touch with Jay below:

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