Half Marathon Nutrition: The Complete Half Marathon Fuelling Guide

Whether you’re training for your first 21.1km or pushing to break a personal best, half marathon nutrition is just as critical as your running shoes. This guide delivers a practical half marathon fuelling strategy, covering pre-race meals, energy gels, hydration strategy, and post-race recovery nutrition.

We’ll walk you through exactly what to eat before a half marathon, how to carb load, and how to fuel during a 2-hour run, with science-backed tips and top product picks from Science in Sport.

What to Eat Before a Half Marathon

Pre-race nutrition is key to maximising stored energy without upsetting your stomach. The ideal half marathon pre-race meal should be consumed 2.5 to 3 hours before your start time, and should prioritise low-fibre, high-carb foods.

Smart Meal Ideas:

• Two slices of toast with honey and banana
• A bowl of white rice with egg or jam
• A smoothie made with oats, banana and low-fat yoghurt

Fuel tip: SiS GO Energy Bar – great for light, pre-run fuelling if you're short on prep time.

Half Marathon Carb Loading

Half marathon carb loading should begin around 48 hours before race day. By increasing carbohydrate intake, you raise glycogen stores in the muscles and liver, helping you run harder and longer without hitting the wall.

How to Carb Load for a Half Marathon:

• Increase daily carb intake to 8–10g per kg of body weight
• Focus on white bread, rice, pasta, potatoes and energy drinks
• Limit fibre and fat to reduce bloating

Race prep essential: SiS Beta Fuel – delivers up to 90g of carbs per serve in an efficient, gut-friendly formula.

Half Marathon Fueling Strategy

Your half marathon fueling strategy depends on your expected finish time and race intensity. For most runners, a 21.1km race takes 1.5 to 2 hours, requiring regular carbohydrate intake to maintain blood glucose and delay fatigue.

Fuel During Half Marathon (2 Hours Plan):

Sample below

• 30 mins: Beta Fuel + Nootropics Gel + 150ml water
• 60 mins: Beta Fuel Gel + 150ml water
• 80 mins: Beta Fuel Chew or another Gel + water
• 100 mins (optional): Beta Fuel Gel if running closer to 2 hrs

Shop Energy Gels for Your Half Marathon:

• SiS Beta Fuel Gel + Nootropics
• SiS GO Isotonic Gels

Hydration Strategy for Half Marathon

Your half marathon hydration strategy should begin 24 hours pre-race and continue through the finish line. Dehydration affects temperature regulation, muscle contraction, and perceived exertion.

Key Guidelines:

• Hydrate regularly the day before
• Drink 500–750ml of fluid 2–3 hours before race start
• Sip water or electrolyte mix with every gel
• Replace electrolytes during longer races or in hot/humid conditions

Top choice: SiS GO Electrolyte Powder



Supports endurance with added sodium, potassium, and magnesium.

Half marathon electrolyte replacement is especially important for runners with high sweat rates or cramp history.

Post Half Marathon Recovery Nutrition

After 21.1km of racing, your body needs a blend of protein and carbohydrates to repair muscles and replenish glycogen stores.

Post-Race Recovery Plan:

• Within 30 minutes: Recovery shake or meal with 20–30g protein + 40–60g carbs
• Rehydrate with water + electrolytes
• Eat a full meal within 2 hours post-run

Quick recovery: SiS REGO Rapid Recovery



Scientifically balanced to promote full-body recovery after endurance efforts.

Half Marathon Race Day Nutrition Plan – Summary

Shop Energy Gels for Your Half Marathon

All SiS products are Informed-Sport tested and trusted by elite runners like Eilish McColgan. Get race-day confidence with gels, drinks, chews, and recovery formulas.

Browse the full SiS range
Perform strong. Recover smarter.

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.

FAQs: Half Marathon Nutrition

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