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Running a half marathon is demanding and a must for those with the goal of completing a full marathon. For these runners, or those who are looking to improve their PB, nutrition plays a pivotal part in endurance performance and can be the difference between a good and a great time.

Training Nutrition

When training for a half marathon, there will be numerous training runs that last under 90 minutes where you can usually rely on taking on an electrolyte drink and 1-2 energy gels. However, running 13.1 miles will be different for many people and require an increase in intensity for the desired performance outcome. For this reason, it is important to get accustomed to your race day nutrition:

Morning fuel: Your breakfast will be one of the most important meals you consume and will ensure you are fully fuelled when you cross the start line, so make sure you are comfortable with it and it works for you.

On the go feeding: Fuelling while running is key, so get confident at consuming fluid and gels whilst running at pace.

Carbohydrate intake: Fuel for the work required throughout your training weeks(1). During short or low intense sessions, reduce carbohydrate intake. However, it’s important to practice your race-day fuelling plan during longer sessions, so that your body adapts to the work. Here, you should practice taking in 60-90g of carbohydrate per hour(2).

Sweat rate: How much you sweat will dictate how much fluid you need to take-in. Aim to not lose any more than 2-3% of your body mass to maintain hydration and be ready to train the next day(3).

Recovery: The faster you recover, the better quality your training will be and the more adaptations you will get. See the Post Training/Racing: Recovery section at the end of the guide for more information.


Pre TrainingDuring

Hydration Ensure you are fully hydrated. Drink 500 – 1000ml of fluid at least 4 hours prior to your training run. Use GO Electrolyte or Hydro to increase fluid retention. Work out how much you are sweating (per hour). Try not to lose more than 2-3% of your body mass through sweating .For longer sessions over 1 hour, run a circuit that stops by your house. This will allow you to re-hydrate. Use Hydro and/ or GO Electrolyte to replace electrolytes lost through sweat.
Energy When preparing for a run over 10km increase carbohydrate the day before. Use GO Energy between meals to increase glycogen stores, practicing for pre race carbohydrate loading. Focus on electrolyte and fluid intake for shorter runs. For longer runs, aim to take on 60-90g of carbohydrate per hour. This can come from 3 GO Isotonic Gels or a combination of GO products. Find the ones that work for you!
Recovery Ensure that you rest well between runs as this is where adaptations take place. Overtraining is common in endurance runners. Aim to get the same amount of sleep each night throughout your training period. N/A
Caffeine A pre training GO Caffeine Shot can help decrease your perception of fatigue and increase concentration during your runs. Take 30 minutes before your session. N/A

Race Day Nutrition

Always make sure that you practice your full race day nutrition routine well before race day itself. Follow these tips, guidelines and examples and smash your PB!

Pre Race

Carbohydrate loading: Our muscles can store up to 400-500g or around 2000kcal of glycogen to be used as energy. Glycogen is the main fuel you will use during your race and is stored when you consume carbohydrate. Unlike longer races, half marathon ‘carbohydrate loading’ should focus on increasing carbohydrate intake in the 24 hours before the race and the pre-race breakfast. Unlike traditional ‘carbohydrate loading’, you don’t necessarily need to increase carbohydrate intake in the 48 hours before the race, but aim for 3-5g of carbohydrate per kilo of your body weight as shown in the table below.

Breakfast: Have breakfast 2-3 hours before the race. This should be part of your ‘carbohydrate loading’ regime as your glycogen stores decrease over night. This should involve normal breakfast foods with around 1-3 grams of carbohydrate per kg of body weight as shown below:

Dinner (night before)Breakfast

  • 300g spaghetti
  • 100g chopped tomatoes
  • 2-3 slices of garlic bread
  • 500ml GO Energy
  • 300g low fat yoghurt with mixed berries
  • 2 slices of toast with jam
  • 1 small bowl of cereal
  • 250ml fresh orange juice

Hydration: Pre race hydration is key. Aim to drink 500ml-1000ml of fluid in the build up to the race, ideally 500ml 2-3 hours at breakfast and 500ml in the build up to the event. Don’t drink just water, GO Electrolyte or Hydro can increase fluid absorption and retention(4), meaning there will be less stops for the toilet during the race

During the Race

During Race
  • Aim not to lose more than 2-3% of your body mass throughout the event. This usually means consuming 500 ml of fluid per hour depending on sweat rate and temperature/ humidity
  • Rehydrate using an electrolyte drink: Hydro provides a precise 30mmol/L of Sodium, which will help retain the fluid
  • A GO Caffeine Shot consumed just before you start may increase concentration and endurance performance
  • Focus should be on hydration and carbohydrate intake
  • After 30 minutes of the race, aim to take on 60g carbohydrate per hour. This can be achieved through food and fluid sources; energy bars and/or energy gels
  • Along with appropriate hydration and fluid intake, this could come from: 3* GO Isotonic Energy Gels or 1* 500ml GO Electrolyte & 2* GO Isotonic Energy Gels
  • GO Isotonic Energy gels are preferred by endurance athletes as they easily carried in a race belt and do not require fluid for easy digestion


Racing depletes muscle glycogen stores, causes muscle damage and results in fluid loss. Your recovery nutrition should therefore focus on both carbohydrates and protein. REGO Rapid Recovery can be used within 30 minutes of finishing a race to provide carbohydrates and protein to kick-start the recovery process. Follow the below points for your post-race recovery:

  • • REGO Rapid Recovery shake immediately post-run
  • • Carbohydrate based meal with protein and vegetables within 2-3 hours of finishing
  • • Replace 150% of fluid lost in the 2-4 hours post-run(3)


  1. Impey, S. G., Hammond, K. M., Shepherd, S. O., Sharples, A. P., Stewart, C., Limb, M., … & Close, G. L. (2016). Fuel for the work required: a practical approach to amalgamating train‐low paradigms for endurance athletes. Physiological reports4(10), e12803.
  2. Jeukendrup, A. (2014). A step towards personalized sports nutrition: carbohydrate intake during exercise. Sports Medicine44(1), 25-33.
  3. Casa, D. J., DeMartini, J. K., Bergeron, M. F., Csillan, D., Eichner, E. R., Lopez, R. M. & Yeargin, S. W. (2015). National Athletic Trainers’ Association position statement: exertional heat illnesses. Journal of Athletic Training50(9), 986-1000.
  4. Thomas, D. T., Erdman, K. A., & Burke, L. M. (2016). Position of the academy of nutrition and dietetics, dietitians of canada, and the american college of sports medicine: Nutrition and athletic performance. Journal of the Academy of Nutrition and Dietetics116(3), 501-528.
  5. Baker, L. B., & Jeukendrup, A. E. (2014). Optimal composition of fluid‐replacement beverages. Comprehensive Physiology, 4, 575-630
Written By

Ted Munson (Performance Nutritionist)

Ted is a Performance Nutritionist here at Science in Sport.