marathon race day nutrition

The Ultimate Guide to Marathon Race Day Nutrition

By Danny Webber
Danny Webber is a SENr registered practitioner, an ISAK certified Anthropometrist and a UK Anti-Doping accredited adviser.
| Updated on July 12, 2023

Now that you’re fully prepared for the marathon after maximising your body’s internal carbohydrate stores and hydration levels, this third and final blog of the series will outline the last minute touches to complete your race day nutrition strategy.

So, what to eat during a marathon?

The time during the postprandial period (between your pre-race meal and the start of the race) should be spent doing whatever you need to do in order to focus on your performance.

You may even want to just relax and not think about it, but whatever you choose it should be something you’ve done regularly in training.

One thing you should not do is worry about what to eat on race day, as again, this will be what you’ve practiced in preparation for this event.

With this in mind, having a good idea of how much you should drink before a race is important to ensure you turn up to the start line well hydrated. Drinking water is a given, but including an electrolyte supplement may optimise your hydration status.

Other nutrition strategies that will have been well practiced in training are the use of preferred ergogenic aids.

Caffeine Supplementation

Caffeine is one of the most researched ergogenic aids and is regularly used to enhance endurance running performance (Graham & Spriet et al., 1991; McLellan et al., 2004; Goldstein et al., 2010).

Caffeine enhances cognitive function through its primary site of action, the central nervous system. It also influences substrate metabolism by increasing the utilisation of fatty acids for energy, thus sparing muscle glycogen for the latter stages of the race.

Low-moderate dose of caffeine between 3-6mg/kg appears to be sufficient for enhancing endurance performance (Goldstein et al., 2010). Having a supplement containing 200-250mg caffeine is an ideal dosage for endurance athletes.

Concentrations are elevated in the bloodstream after just 15 minutes and peak 1 hour after ingestion (Harland, 2000), therefore having a quick, convenient supplement like a shot or caffeine gum 15-30 minutes prior to competition can raise and maintain blood concentrations to enhance performance throughout the marathon.

Other supplements that may enhance endurance performance include nitrates e.g. concentrated beetroot, but this can also be improved from food sources (Murphy et al., 2012).

Sodium bicarbonate may also be of benefit (George & MacLaren, 1998) however this should be supplemented with caution as it may induce lower GI issues.

Co-ingestion of sodium bicarbonate with a high carbohydrate meal 2-3 hours prior to exercise may best to reduce GI symptoms (Carr et al., 2011).

What To Eat On Race Day

During the race it is important to remember to drink little and often to prevent extreme dehydration.

Some degree of dehydration can be expected at the end of the race but replacing water and salts lost through sweat by drinking a combination of water and carbohydrate electrolyte drinks and gels is essential to maintain hydration and maximise performance.

In the previous blog carbohydrate intake during training was highly recommended in nutrition for endurance athletes when training duration exceeds 90 minutes.

The world’s best athletes run for at least 2 hours to complete the 26.2 miles of a marathon, so even they will top up energy levels with carbohydrate drinks and gels.

Just to recap, 30-60g carbohydrate per hour is recommended to increase the availability of the body’s preferred energy source (Jeukendrup, 2014).

Energy gels typically contain 25g carbohydrate so having 2 of these per hour along with mouthfuls of energy/sports drinks can provide 60g carbohydrate per hour.

Competitors who have an expected finish time of more than 4 hours may also benefit from an additional dose of caffeine during the race day to promote mental alertness in the final 60-90 minutes. Therefore, you should focus on nutrition during marathon before the race.

Also, Learn about carbohydrates for athletes

Take Home Messages

  • Practice ALL nutrition strategies extensively before the event so you’re comfortable with its application.
  • Caffeine is an effective ergogenic aid before and during competition at intakes of 3-6mg/kg body mass.
  • Nitrates, both via food (beetroot, leafy greens) and supplements are also beneficial prior to endurance exercise.
  • Maintain hydration during the race day by replacing lost water and salts through sweating by drinking water and carbohydrate-electrolyte solutions.
  • Consume carbohydrates in drinks, gels (and foods if preferred) during the race at a rate of 30-60g/hour.

Also Read: What to Eat Before a 10K Race – Fuelling for a 10KM Race


Carr, A. J. et al. (2011). Effect of Sodium Bicarbonate on [HCO3 –], pH, and Gastrointestinal Symptoms. International Journal of Sport Nutrition and Exercise Metabolism, 2011, 21, 189-194.

George, K.P., & MacLaren, D. P. M. (1998). The effect of induced alkalosis and acidosis on endurance running at an intensity corresponding to 4mM blood lactate. Ergonomics, 31, 1639-1645.

Goldstein, E. R. et al. (2010). International society of sports nutrition position stand: caffeine and performance. Journal of the International Society of Sports Nutrition, 7, 5-20.

Graham, T. E., & Spriet, L. L. (1991). Performance and metabolic responses to a high caffeine dose during prolonged endurance exercise. Journal of Applied Physiology, 71, 2292-2298.

Harland, B. (2000). Caffeine and nutrition. Nutrition, 16, 522-526.

Jeukendrup, A. (2014). A step towards personalized sports nutrition: carbohydrate intake during exercise. Sports Medicine, 44, S25–S33.

McLellan, T. M., & Bell, D. G. (2004). The impact of prior coffee consumption on the subsequent ergogenic effect of anydrous caffeine. International Journal of Sport Nutrition & Exercise Metabolism, 14, 698-708.

Murphy, M., Eliot, K., Heuertz, R. M., & Weiss, E. (2012). Whole beetroot consumption acutely improves running performance. Journal of the Academy of Nutrition and Dietetics, 112, 548-552.

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