Supplements for Marathon

Supplements for Marathon

In this article we tell you about supplementation planning for running a marathon.

Marathon: the ultimate test in athletics

The 42,135 metres that make up the marathon has become one of the most popular events today amongst Long Distance runners.

As we have pointed out in the previous articles grouped together under this theme of endurance sports, running a successful marathon depends on many factors. Importantly, this includes: nutrition and supplementation.

While we’ve already written about the category 1 supplements, the most effective performance enhancers in endurance sports, today we focus on the Marathon event.

Planning your training

As noted above, the fundamental challenge of a long distance event such as the Marathon is to arrive at the event with having worked on a good training schedule throughout the process, approached from different perspectives.


  • Correct planning of Volume and Intensity of Training Loads.
  • Assimilation of Training Loads and Rhythms.
  • Periodisation of Nutrition and Supplementation in the different phases of the process.
  • Optimal and healthy weight for the test.
  • Correct rest and control of stress factors.
  • Avoiding Injuries.

Marathon training

Obviously, training for a marathon is a process that can take months.

Limiting factors of a marathon

That said, we must also mention the LIMITING FACTORS or problems that can and do occur in endurance tests:

  • The well-known “Wall”, which refers to the moment when extreme fatigue appears, either due to a lack of energy substrates during the test, or due to a lack of muscle strength that causes a loss of efficiency in movement.
  • Gastrointestinal problems that can cause vomiting, diarrhoea, discomfort.
  • Arriving with overweight due to incorrect nutrition throughout the process.


Do you know why and how to prevent «the Wall»? Visit this link.

What does performance in the Marathon depend on?

On the other hand, we also need to take into account which variables are the decisive factors in the marathon:

  • Aerobic Threshold
  • Maximal Lactate Steady State.
  • Running Efficiency (correct technique to ensure energy efficiency).
  • Fat Oxidation Rate and Fat-Max Improvement.
  • Exogenous Carbohydrate (CHO) Input Variables.
  • Endogenous CHO variables: storage status of glycogen and glucose in the blood
  • Running Economy: Strength
Given these variables, which are trainable throughout the Training Process, we are going to focus on the exogenous variables of HCO.

With Carbohydrates, you will succeed

It’s worth remembering that it’s important to teach the body how to maximise the efficiency of fat oxidation in order to delay the glycolytic metabolic pathway and thus improve the metabolic efficiency of this type of test.

Let’s remember that the rhythms and training zone of a marathon are fundamentally those in which we work on aerobic zones, with a predominant metabolic pathway of fat oxidation.


So, the more efficient this metabolic pathway is, the less glycogen dependent it is.

Although it is a metabolic route that plays an important role in the marathon.

Nutritional Periodisation, therefore, is a hugely important factor in a successful marathon, taking into account the strategies and ergogenic aids in each moment and on the specificity of each training mesocycle.

This is what we’re getting at in this article!

Nutritional strategies

Here are some of the strategies aimed at optimising energy efficiency in long-distance events such as the marathon.

Always take into account the time of season with the loads – intensity of the training.

Training Low, Compete High

Low training in CHO and some competition in CHO.

There is currently a lot of research related to this strategy being followed by many professional long distance runners and triathletes.

But what does it involve?

This type of strategy refers to training with muscle and liver glycogen deposits at very low levels, in order to improve and create positive adaptations at a molecular level on the endurance athlete.

Changes that will be modulated as a result of the expression of certain genes that optimise the metabolism of fatty acids.

Knowing that, one of the responsible ones at a metabolic level is related to an increase of protein kines activity regulated by AMP (AMPK).


There is a known correlation between low availability of glycogen and increased activity of this metabolic pathway.

There are different nutritional strategies for this purpose, and they may or may not be combined. We’ll not go into this in detail, but it’s always necessary for these strategies to be supervised and controlled by a sports nutritionist and trainer..

We would find: training while fasting, training with high levels of HCO but sleeping with low levels, low carbohydrate diet etc.

Training High

High Carbohydrates

The other approach, bearing in mind that it’s also necessary to optimise the availability of carbohydrates in order to efficiently maintain a training program with high workloads and intensities.

This strategy can also be carried out at another time in the training programme with high volumes of kilometres and demanding intensities.

It must be taken into account that the daily amounts depend on multiple aspects such as: training load, profile of the athlete, lifestyle of the athlete, weekly calorie expenditure, among others.

The idea is also to achieve adaptations to the assimilation of HCO, in order to avoid gastrointestinal problems that can occur in long term events (> 2’5 hours), if the body has not been “taught” to efficiently absorb HCO under a situation that involves high physical stress such as a marathon.

Marathon Nutrition

Apart from the above, and thinking about the day of the event.

There are several VERY IMPORTANT aspects that should be considered when considering the nutritional strategy of the marathon:

  • Weather conditions: temperature on the day of the event and humidity level (these are factors that directly affect sweating levels, and therefore maintain a water and salt balance in accordance with the athlete’s sweating rate).
  • Diet in the days leading up to the test as well as hydration levels
  • Estimated rhythms of the athlete to program the intakes as well as the amounts they will need, taking into account the estimated time.
  • Location of provision points as well as knowing what the athlete can find in each one of them.
  • Time of the competition to schedule the breakfast with enough time for correct digestion (it would be convenient to introduce HCO with low glycemic index, to avoid a peak of insulin that slows down the rate of fat oxidation).

What to eat before a marathon?

If everything has been planned correctly and a good intake has been made the previous 3 or 4 hours, no extra consumption would be necessary at this time.

However, many runners have half a banana, a gel containing fructose (low glycemic index) and small doses of an isotonic drink.

Aid station

What to have during a marathon?

Of course, following to the nutritional periodisation plan throughout the preparation the athlete will try the supplements they take with them on race day, and will have previously rehearsed the “times and amounts to take”.

As mentioned above, for efforts lasting more than 2 hours, the basic recommendations would be as follows:

  • 30 grams of CHO/HOUR in the first 60 minutes of the event.
  • 30-60 grams of CHO/HOUR from the 2nd hour
  • Up to 90 grams of CHO/HOUR 3rd hour.*

*As Diego Moreno points out, in the book “Manual for endurance sports”.

However, this may be too much for a normal athlete to absorb, so I would recommend a maximum intake of 60 grams/hour for a marathon.

As we pointed out at the time, and in order to improve the absorption of carbohydrates by the body and the digestive system, it’s best to combine GLUCOSE + FRUCTOSE in a ratio of 2:1.

Therefore, when choosing which supplement to take during the event, its important to study the labelling of the products to be consumed.

Mouthwash is also an optimal strategy at times when the athlete feels they don’t need energy although they begin to suffer from gastrointestinal discomfort. You can learn more about it here.

What supplements to take during a Marathon?

As a runner, you need to know that the objective of this intake of HCO as an energetic substrate is for it to be quickly and easily assimilated and digested by the body, and there may be glucose in the blood.

So the products we choose must be easily absorbed and quickly assimilated, avoiding excess work for the digestive system.

Energy bars and gels

Having energy bars, besides being difficult to chew during the race, are not the most advisable for a marathon.

You need an intake that does not need to be chewed, that is ingested quickly.

That’s why energy gels are the most recommended; there are also HCOs in sweet format, and drinks high in HCO.

Mineral salts

On the other hand, the degree of sweating must be taken into account, and a good, not excessive, hydration must be maintained throughout the event, with small intakes of water and/or isotonic drink.

It’s also advisable to take extra salt in the most convenient format for the athlete, such as mineral salt or electrolyte capsules.


Finally, we would like to mention CAFFEINE, which we have already discussed.

Caffeine is easily swallowed, blood levels rise and the peak is reached after approximately 60 minutes (which is useful for planning the run nutrition strategy).

What does the science say?

In a study carried out in the late 1970s, it was found that caffeine taken one hour before exercise increased the concentration of plasma GA (fatty acids) and improved performance (Costil et Al. 1977).

A meta-analysis of published studies on performance and caffeine use suggested that the magnitude of the effect of caffeine intake improved when exercise duration was increased.

This results in ergogenic support for marathon runners, as well as a reduction in the subjective perception of effort (Doherty y Smith, 2005).

On the other hand, the results of the Hogervorst et al’s (1999) study regarding the improvement of cognitive functioning (motor skills, attention and memory) are remarkable.

The question now is, what is the optimal dose in a marathon?

With regard to dosage, the recommended dosage would be 2mg / kg body weight (no more than 3.5mg / kg), which can be administered halfway through the test.


As we can see, correct planning of the nutrition strategy for a marathon is vital to able to maintain optimal energy levels, to delay and avoid fatigue, and for success.

It is recommended that a sports nutritionist, together with your trainer, plan the dosage and timing of the nutritional plan throughout the preparation.

Bibliographic sources

  1. Cardona C, Cejuela A, Esteve J. Manual para Deportes de Resistencia. All in Your Mind Training System. (2019)
  2. Jeukendrup A, Gleeson M. Nutrición Deportiva. Ediciones Tutor (2019)
  3. Jeukendrup, A.E. Periodized Nutrition for Athletes. Sports Med (2017) 47(Suppl 1): 51.
  4. Jeukendrup AE, McLaughlin J. Carbohydrate ingestion during exercise: effects on performance, training adaptations and trainability of the gut. Nestle Nutr Inst Workshop Ser. 2011;69:1–12

Related Entries

  • Do you want to improve your running technique? You might be interested in reading the following article.
  • How to prepare for your First Marathon. More information.
  • We tell you everything you need to know about Nutrition in Half Marathons. Click here.
Review of Supplements for Marathons

Recommendations - 100%

Carbohydrates - 100%

Gels - 100%

Mineral salts - 100%

Cafeine - 100%


HSN Evaluation: 5 /5
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About Isabel del Barrio
Isabel del Barrio
Isabel del Barrio really loves sport, demonstrating it from a very young age and sharing her enthusiasm and knowledge to this day
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