marathon training diet

Marathon Training Diet – The Best Nutrition for Marathon Training

By Danny Webber
Danny Webber is a SENr registered practitioner, an ISAK certified Anthropometrist and a UK Anti-Doping accredited adviser.
| Updated on June 27, 2022

Training for a marathon requires a lot of commitment and determination. It is one of the most challenging events you can put your body through, so getting your nutrition right is a massive bonus to support your training and keep you fit and healthy. As you edge closer to the competition it’s important to have practiced your race day nutrition so you can maximise your performance when it matters most. Get the most out of your training and arrive at the start line with these practical nutrition strategies.

Marathon Training Diet

What you eat should reflect your energy requirements to fuel your daily training volumes. Consistently under fuelling your body during periods of intense training can negatively impact your performances, but also lead to illness and injury. Many years’ research has consistently shown that muscle glycogen is the primary energy source during endurance exercise, and depletion of these stores is directly linked to fatigue (Bergstrom et al., 1967). Carbohydrates supply the muscles with glycogen and therefore are considered to be energy foods.

Diet Before a Marathon Training

In the hours before training you should aim to include carbohydrates in your meals to fuel your run. The timing of your pre-race meal and what you eat will be down to your preference, however allow sufficient time (2-4 hours) for the food to be digested to prevent gastrointestinal issues during the race.

Here are a few examples to get you started:

  • Porridge with dried fruit and honey
  • Bagels with peanut butter
  • Eggs on toast & fruit juice
  • Smoothie

Start thinking about what foods work best for you to plan for what to eat before the marathon.

What to Eat During a Marathon Training 

As the duration of your training increases beyond 90 minutes, you should also be practicing consuming carbohydrates during training to maintain energy levels. This can be done through carbohydrate-electrolyte drinks, gels or solid foods. For a marathon, you should aim to consume approx. 60g carbohydrate per hour (Jeukendrup et al., 2014). Two Energels provide 50g carbohydrate. Staying hydrated is also essential during prolonged training to replace fluids and electrolytes lost through sweat.

As previously mentioned, it’s important to monitor your strategies as gastrointestinal issues may occur. Minimizing this risk is vital to improving performance.

Nutrition Required After a Marathon Training

Recovery is just as important as the training session. If your body doesn’t recover properly then you increase the risk of illness and injury and training performances may be hindered. High quality proteins help to repair damaged tissue and promote training adaptations, and 25-30g leucine rich whey protein is recommended to maximise this response. It’s also important to replenish your muscle glycogen stores and rehydrate after training.

Milk is the best thing to have after intense training as it is more effective for stimulating protein synthesis and rehydration, improving subsequent exercise performance and attenuating exercise induced muscle damage than any commercially available sports supplement (Karp et al., 2006; Shirreffs et al., 2007; Cockburn et al., 2010). Milk is also rich in calcium to promote bone health. If you require additional carbohydrates then you can also make a smoothie by including antioxidant rich fruits.

Check out my previous article on what to eat after a workout.

Diet for Low-Intensity Marathon Training and Rest Days

If you’re doing a short 30 minute run, does that mean you need a huge bowl of porridge before it? No, it doesn’t. So what do you eat on easy training days and rest days?

Remember that carbohydrates are the energy foods, so you don’t need as much on these days. Reduce carbohydrate intake and increase protein and include high quality unsaturated fats (e.g. omega-3).

Easy/low-intensity runs can be done before breakfast with the goal of increasing training adaptations (Van Proeyen et al., 2011). This helps the muscles to become more efficient at using fat and carbohydrates as an energy source, reducing the reliance on carbohydrates for fuel thus preserving glycogen stores for periods of increased intensity e.g. hill climbs, sprint finish.

Diet for Marathon Week

In the days before the competition, it’s important to ensure your primary energy stores (muscle glycogen) are full and you’re well hydrated so you arrive at the start line ready to race.

Carbohydrate loading diet involves increasing the amount of carbohydrate you eat the day(s) before a competition. It is generally recommended to consume 8-10g carbohydrate per kg of body mass. Therefore if you weigh 70kg, you should aim for 560-700g of carbohydrate. This is the equivalent to 9 large potatoes, 750g raw pasta or 17½ 500ml bottles of Lucozade sport. In other words, a lot of carbohydrates!

Reducing total fibre intake and avoiding large quantities of dairy, fat and protein rich foods are recommended to prevent gastrointestinal discomfort.

Instead, focus on energy dense carbohydrate foods with adequate sources of protein and unsaturated fats, and hydrate well to support muscle glycogen synthesis.

Also Learn about Rugby Player Diet.

Foods for Marathon Training 

Food Intake Carbohydrate (g)
100g porridge oats 70
300ml skimmed milk 15
Tbsp. honey 17
2 tbsp. raisins 25
2 slices wholemeal toast with jam 60
400ml apple juice 40
Mid-morning Snack
1 Energy gel 25
1 banana 25
100g chicken breast 0
100g white basmati rice, raw weight 85
250g passata 15
250g low-fat rice pudding 40
1 banana 25
500ml Hydration formula 11
Afternoon Snack
80g cornflakes (or similar) 73
250ml skimmed milk 12
500ml Lucozade sport 32
100g grilled cod/haddock fillet 0
400g mashed white potato, raw weight 80
2 grilled tomatoes 10
400ml apple juice 40
Total 700g

Pre Marathon Meal Plan

The main preparation has been done the days before race day, so the aim of the pre-race meal is simply to ‘top up’ the already loaded muscle glycogen stores and replenish liver glycogen stores after an overnight fast.

By this point you should have extensively practiced your pre-race meal in training so you’re comfortable with it and should not cause any digestive discomfort. Based on personal preference, a typical pre-race meal will be a combination of the options listed above, and depending on when you eat should contain 1-4g/kg carbohydrate (1g/kg/hour).

For example: a 70kg athlete eating 3 hours before the race (3g/kg/hour) will aim to have approx. 210g carbohydrate.

In the hours leading up to the race you just need to focus on hydration. Water and Nutrition X’s Hydra 10 are recommended to ensure you start the race well hydrated.

**Get 20% off all Nutrition X products using code 20NX.


Bergstrom, J., et al. (1967). Diet, muscle glycogen and physical performance. Acta Physiologica Scandinavica, 71, 140-150.

Cockburn, E., Stevenson, E., Hayes, P., Robson-Ansley, P., & Howatson, G. (2010). Effect of milk-based carbohydrate-protein supplement timing on the attenuation of exercise induced muscle damage. Appl. Physiol. Nutr. Metab. 35: 270–277.

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

Karp, J., Johnston, J., Tecklenburg, S., Mickleborough, T., Fly, A., & Stager, J. (2006). Chocolate milk as a post-exercise recovery aid. Int J Sport Nutr Exerc Metab. 16: 78-91.

Van Proeyen, K., Szlufcik, K., Nielens, H., Ramaekers, M., & Hespel, P. (2011). Beneficial metabolic adaptations due to endurance exercise training in the fasted state. J Appl Physiol 110: 236–245.

Shirreffs, S., Watson, P., & Maughan, R. (2007). Milk as an effective post-exercise rehydration drink. Br J Nutr. 98: 173-180.


What are the best fruits for a marathon training diet?

All fruits are effective in supporting marathon training, so having a wide variety of 3-5 portions a day is the best approach.

What supplements should I take for marathon training?

Supplements are not a necessity for marathon training, and any recommended supplements will be advised based on the individual athlete’s diet and fueling needs. Contact me to discuss your needs. The main considerations might be: 1) Carbohydrate gels 2) Electrolyte tablets 3) Whey protein 4) Vitamin D3 during the winter 5) Omega 3

Why am I gaining weight while training for a marathon?

You are overeating for the training you are doing. A common reason for this is because you are actually underfilling before and during training and therefore overeating when you get home because you’re starving. Get in touch as I can help you with this…

What are the best drinks for hydration during marathon training?

Water is always the best choice throughout the day, but including an electrolyte tablet can help you replace salts lost through sweat during and after training. Cow’s milk is the best option after your long runs to promote recovery.

What is the best last meal before a marathon?

A marathon will typically start in the morning so a combination of (well-practiced) breakfast options such as porridge with banana and honey, breads with jam/honey/peanut butter and fruit juices are all good pre-race breakfast options.

When should you eat after training for a marathon?

Recovery should start very soon after you finish training, especially for your longer weekend runs. A pint of milk or a smoothie is a great option especially for runners who do not have an appetite after training, but this should then be followed by a well balanced recovery meal.

When should I start carb loading for a marathon?

1-2 days before a marathon is ample time to carb load to maximize muscle glycogen stores.

Can you lose weight while training for a marathon?

Yes very easily, so long as you have a well planned nutrition strategy to maintain sufficient energy levels to train and you don’t sacrifice performance for weight loss.

How to avoid marathon training weight gain?

A common reason for gaining weight whilst marathon training is because you are actually underfilling before and during training and therefore overeating when you get home because you’re starving. Get in touch if you need help with this…

What do marathon runners eat for breakfast during training?

Marathon runners should eat what they plan to eat on race day before training, so it is tried and tested, known to work well when performance matters most, and won’t cause any upsets!!

Sign up to my email list

* indicates required

Leave a Comment

Your email address will not be published. Required fields are marked *