Marathon Nutrition: The Complete Marathon Fuelling Guide

29th Aug 2025

Training for 42.2km is no easy feat—but without a solid marathon nutrition plan, all that work could go to waste. Whether it’s your first marathon or your fifth, the right marathon fuelling strategy ensures you don’t hit the wall, stay hydrated, and recover like a pro.

In this guide, we’ll cover:


  • What to eat before a marathon
  • Marathon carb loading
  • Energy gels and hydration timeline
  • Post-marathon recovery nutrition

What to Eat Before a Marathon

Your marathon race-day nutrition plan starts the night before. A well-timed, carbohydrate-rich meal helps top up glycogen stores and sets the stage for optimal performance. On race morning, eat 2.5 to 3 hours before the start to allow time for digestion.

Recommended Pre-Marathon Meal:

  • Two slices of sourdough toast + banana + honey
  • White rice with scrambled eggs or tofu
  • Low-fat smoothie with oats, berries, and honey

Easy option: SiS GO Energy Bar
Compact and digestible, ideal for runners with early start times or low pre-race appetite.

Marathon Carb Loading

Marathon carb loading should begin 2–3 days before the event. This boosts glycogen stores—your body’s premium fuel source during endurance running.

How to Carb Load:

  • Eat 8–12g of carbs per kg of body weight per day
  • Choose low-fibre, easily digestible carbs like pasta, rice, bagels, and energy drinks
  • Limit fat and protein to keep digestion light

Carb boost: SiS Beta Fuel Drink
Delivers up to 90g of dual-source carbs per serve, formulated to maximise absorption.

Marathon Fueling Strategy (Timeline-Based)

A successful marathon fueling timeline prevents energy crashes and delays muscle fatigue. During a 4-hour marathon, your body can burn through up to 2,800 calories. The key: consistent carbs and fluids every 30–40 minutes.

Example Fueling for Marathon (~4hr Finish):

  • Start line (0 mins): Beta Fuel Gel + 150ml water
  • 30 mins: Beta Fuel Chew + water
  • 60 mins: Beta Fuel Chew + water
  • 90 mins: Beta Fuel + Nootropics Gel + water
  • 120 mins: Beta Fuel Gel + water
  • 150 mins: Beta Fuel Chew + water
  • 180 mins: Beta Fuel Gel + water

Top picks:

  • Beta Fuel Gels & Chews – designed for endurance absorption
  • GO Energy + Caffeine Gel – ideal late-race mental boost

Hydration Strategy for Marathon

A strong marathon hydration strategy is essential—especially in warm or humid Australian conditions. As you sweat, you lose sodium, potassium, and magnesium—key for muscle function and performance.

Key Tips:

  • Hydrate regularly in the 24–48 hours pre-race
  • Drink 500–750ml 2 hours before the race
  • Consume 150–250ml water or electrolyte mix every 15–20 minutes during the race
  • Use electrolytes in drinks and gels to aid fluid absorption

Hydration help: SiS GO Electrolyte Sports Fuel
Combines fast carbs with electrolyte support for full endurance performance.

Marathon electrolytes replacement is vital if you sweat heavily or experience mid-race cramps.

Post-Marathon Recovery Nutrition

Crossing the finish line isn’t the end—post marathon recovery nutrition is crucial to restoring glycogen, rebuilding muscles, and rehydrating effectively.

What to Do Post-Race:

  • Within 30 mins: take a recovery drink or small meal with 20–30g protein + 50–70g carbs
  • Rehydrate with water and electrolytes
  • Eat a full, balanced meal within 2 hours

Recovery MVP: SiS REGO Rapid Recovery
Ideal after intense sessions, REGO blends protein, carbs, electrolytes, and vitamins to support full-body recovery.

Marathon Race Day Nutrition Plan – Quick Recap

  1. What to eat before a marathon

    • ✅ High-carb, low-fibre breakfast
    • ✅ Energy bar or sports drink if short on time

  2. Marathon carb loading

    • ✅ 48–72 hours of increased carb intake
    • ✅ Use Beta Fuel to simplify carb counting
  3. Marathon fueling timeline

    • ✅ Fuel every 30–40 mins
    • ✅ Combine gels, chews, and electrolyte drinks
  4. Hydration strategy for marathon

    • ✅ Drink before and throughout the race
    • ✅ Replace key electrolytes
  5. Post marathon recovery nutrition

    • ✅ Prioritise protein + carb recovery shake
    • ✅ Rehydrate and eat within 2 hours
Shop energy gels formulated for marathon performance

FAQs: Fueling for Marathon Performance


How many carbs per hour during a marathon?

Aim for 60–90g per hour. Beta Fuel gels + chews make this easy to achieve with minimal gut distress.


What if I can’t eat before an early race?

Have a gel and sports drink 30–60 mins before. It’s better than skipping altogether.


Is caffeine safe during a marathon?

Yes. Caffeine improves alertness and can delay fatigue, especially in the second half of your run.


Do I need electrolytes in cool weather?

Yes. Sweat loss still occurs, and electrolytes are essential for performance and recovery.


What’s the best energy gel for marathon runners?

Beta Fuel Gel + Nootropics offers 40g carbs + cognitive support. SiS GO Isotonic Gels are best for sensitive stomachs.



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Train smart. Fuel right. Finish strong.



Disclaimer: While these tips can be a game-changer, it’s always best to consult a registered dietitian for personalised advice tailored to your specific needs and goals.