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Mastering the Marathon: Optimal Nutrition for Endurance Athletes

Mastering the Marathon: Optimal Nutrition for Endurance Athletes

Article At A Glance

Pre-race nutrition is crucial for optimal performance, including carb loading 2-3 days before the race.

During the race, focus on easily digestible carbohydrates and fluids based on the event's duration.

Post-race, consume carbohydrate-rich snacks within 30 minutes and consider supplements to prevent deficiencies.

Product Recommendations
Nectar Of The Gods Post Workout Nutrition by UM Sports
Rehydration Performance Fuel by Endura
Sports Energy Gel by Endura

Running a marathon is a remarkable achievement that demands dedication, perseverance, and meticulous planning.

Proper sports nutrition can help athletes optimise their performance, reduce the risk of injury, and support overall health and wellness. Athletes must develop an individualised nutrition plan considering their unique needs and goals.

In this blog, we will delve into pre-race nutrition, race day nutrition, post-race recovery, and common deficiencies that athletes should be aware of to support their performance and recovery for a marathon.

Pre-Race Nutrition

Before the big race, focusing on your pre-race nutrition is essential to ensure your body is optimally fuelled and prepared.

Carb loading

Carb loading is a nutritional strategy that occurs 2-3 days leading up to race day and is used by endurance athletes to increase stored energy through glycogen for better performance. ​Each individual will vary, but typically on each day of loading:

  • Male athletes require ~7-10g of carbohydrate per kilogram body weight (e.g.~525-750g carbohydrate per day for a 75kg athlete).
  • Females athletes roughly ~5-8g of carbohydrate per kilogram body weight each day that they are loading (e.g.~300-480g carbohydrate per day for a 60kg athlete).

Pre-race meal for an early morning race

  • 1-2 hours before the race
  • 1-4 g carbohydrate per kg of bodyweight
  • Light + low fibre
  • Consume fluid (400 – 600 mL)

Some suitable pre-event light snack ideas include: Tetra pack flavoured milk + muesli bar, peanut butter on toast, crumpets with banana + honey, and creamed rice.

Race Day Nutrition

During your race, your focus should be on carbohydrates and fluid.

For events lasting 60 minutes to 2.5 hours

  • Consume 30-60 grams of carbs per hour
  • 200-300 ml of sports drink if having one carb gel
  • 400-600 ml of sports drink if having two carb gels
  • Should be easy-to-digest carbohydrate-rich options with minimal fat, fibre and protein

For events lasting 2.5 hours to 3 hours +

  • Consume up to 90 grams of carbs per hour
  • It is recommended to include a combination of solid and liquid options

Post-Race Nutrition

Congratulations, you've crossed the finish line! Now it's time to focus on post-race recovery and nutrition to aid muscle repair and replenish depleted energy stores.

Within 30 minutes of finishing the race, consume a carbohydrate-rich snack to replenish glycogen stores and aid in muscle repair. Aim to consume carbs at a rate of 1.0-1.2 grams per kilogram of body weight per hour within 1-4 hours post-event.

Chocolate milk, a banana with peanut butter, or a sports recovery drink (e.g. Nectar of The Gods or Endura Performance Fuel) are excellent options.

Fluid strategy

Proper hydration before, during, and after training and competition will help reduce fluid loss, maintain performance, lower submaximal exercise heart rate, maintain plasma volume, and reduce heat stress, heat exhaustion, and possibly heat stroke (von Duvillard et al., 2004). Staying hydrated is paramount to prevent dehydration and maintain performance.

 Aim to consume 150-350 ml of fluids every 15-20 minutes during the race, depending on sweat rate and weather conditions.

If your workout lasts more than two hours, you should add sodium to the fluids you drink. Anybody who loses more than 3–4 g of sodium from perspiration should also include it in their fluid intake. Head to the (AIS,2021) website for more information on fluid intake during a marathon

Common Deficiencies of Endurance Athletes

A common deficiency among endurance athletes is iron, a mineral the body needs for growth and development. Due to the unique demands of marathon training, iron needs can be up to 70% greater than the general population's, making endurance athletes more susceptible to iron deficiency.

Compromised iron levels are typically associated with symptoms of lethargy and fatigue. In athletes, it may manifest in reduced training and performance outcomes or a suppressed ability to respond/adapt to training stimuli.

To prevent iron deficiency, include iron-rich foods such as lean red meat, fortified cereals, spinach, and lentils (AIS - Iron Information). To help your body absorb iron, consume foods high in vitamin C or carotenoids (e.g. oranges, carrots, and apricots) at the same time as your iron-rich foods. If needed, consider incorporating iron supplements such as Fusion Iron Adv.


Recommended Supplements

Whole foods should form the basis of your nutrition; however, the increased energy expenditure of endurance and high-intensity athletes' makes the food-first approach challenging and increases their risk of nutritional deficiencies.

Concentrated doses of those nutrients are often needed during or after exercise to correct and prevent deficiencies (Close et al., 2022).

During race supplements: Energy Gels are marathon runners' most popular sports food. They are considered a 'Group A' sports food due to the strong scientific evidence that supports using them in specific sporting situations. Energy chews and bars are effective, practical, and popular supplements that runners typically incorporate into their fuelling strategy.

Post-race supplements: Post-race nutrition is essential for aiding muscle repair and replenishing depleted energy stores. Some popular supplements include



Fueling your body is critical to successful marathon training and performance. Pre-race nutrition sets the foundation for optimal performance, while race day nutrition and post-race recovery strategies ensure you stay energised and recover efficiently.

Identifying and addressing common nutrient deficiencies further supports your overall well-being as an endurance athlete.

Remember to personalise your nutrition plan based on your needs and consult a registered dietitian or sports nutrition expert for tailored advice.



Teigen Faux, Exercise Physiologist (Honours)

Stephen Brumwell, Nutritionist (ANTA #40048) for Scientific Accuracy

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