Fueling strategies during half-marathons and marathons.
Long-distance running isn’t just a test of your legs — it’s a test of your fuel tank.
In events like half-marathons (21.1 km) and marathons (42.195 km), your performance is as much about energy management as it is about pace. Get your fueling right, and you’ll finish strong. Get it wrong, and you’ll meet the dreaded “wall.”
This guide breaks down what to eat, when to eat, and how to hydrate so your body can go the distance.
1. The Energy Challenge in Long Runs
Your body stores two main fuels:
- Glycogen (stored carbs in muscles & liver) – enough for ~90–120 minutes of running at moderate-high effort.
- Fat – massive reserves, but burns slowly and requires oxygen.
Why you hit “the wall”:
Around the 30–35 km mark in a marathon, glycogen runs low, and your body is forced to rely more on fat — slowing your pace and making every step harder. Strategic fueling delays this depletion.
2. Pre-race Nutrition: 24–48 Hours Before
Goal: Maximize glycogen stores without overloading your digestive system.
Carb Loading Basics:
- Duration: 2–3 days before race day.
- Carbs: 7–10 g/kg of body weight per day.
- Examples: rice, pasta, oats, potatoes, fruit, bread.
- Protein: Moderate (lean meats, eggs, dairy).
- Fats & fiber: Keep moderate to low to reduce gut stress.
Sample Pre-Race Day Menu:
- Breakfast: Oatmeal with banana & honey
- Lunch: Chicken with white rice & steamed vegetables
- Snack: Rice cakes with peanut butter
- Dinner: Pasta with light tomato sauce & grilled fish
Hydration: Sip water consistently; avoid overdrinking.
3. Race Morning Fuel
Goal: Top up glycogen & ensure steady blood sugar without gut discomfort.
- Timing: Eat 2.5–3 hours before race start.
- Carbs: 1–4 g/kg body weight.
- Protein & fat: Keep low to aid digestion.
- Examples: white toast with jam, banana, small portion of oatmeal, sports drink.
30–60 minutes before start:
Optional small snack (gel, banana, sports drink) if you’ve eaten early.
4. Fueling During the Race
Half-Marathon (21.1 km):
- If your race is <90 minutes, you may not need mid-run carbs.
- If >90 minutes, aim for 30–60 g of carbs per hour.
Marathon (42.195 km):
- Start fueling early (around 30 minutes in).
- Aim for 60–90 g of carbs per hour (practice in training).
- Combine glucose & fructose sources for better absorption.
Common Carb Sources:
- Energy gels (20–25 g carbs each)
- Chews or gummies
- Sports drinks
- Bananas or small dates (for slower events)
Example Marathon Fuel Plan (3:45–4:15 finish time):
- Start: 500 ml sports drink during first 30 minutes
- Every 30–35 min: 1 gel + small sip of water
- Aid stations: Alternate water & electrolyte drink
5. Hydration & Electrolytes
Hydration is not just about water — it’s about fluid + electrolytes.
General Guidelines:
- Drink 400–800 ml per hour depending on sweat rate & conditions.
- Alternate between water and electrolyte drink (with sodium, potassium, magnesium).
- In hot races, aim for 500–700 mg sodium/hour.
Signs You Need More Electrolytes:
- Muscle cramps
- Dizziness or lightheadedness
- Salt stains on clothes
6. Post-race Recovery Fuel
Goal: Replenish glycogen, repair muscles, restore fluids.
- Timing: Within 30–60 min post-finish.
- Carbs: 1–1.2 g/kg body weight.
- Protein: 20–30 g (whey shake, chocolate milk, lean meats).
- Fluids: Replace 150% of fluid lost over next 4–6 hours.
Sample Recovery Meal:
- Grilled chicken wrap with sweet potato
- Fruit smoothie with yogurt
- Water + electrolyte tablet
7. Practice Your Race-day Nutrition
Never try new foods or drinks during a race.
- Test your gels, drinks, and timing on long training runs.
- Adjust based on weather — hotter days = more fluids & electrolytes.
- Keep a nutrition log to track what works.
Quick Fueling Checklist
✅ Carb-load 2–3 days before
✅ Eat light, carb-rich breakfast on race day
✅ Start fueling early during the race
✅ Include electrolytes in hydration
✅ Replenish carbs & protein after
Final Takeaway
In long-distance running, fueling is training. The right nutrition plan can mean the difference between coasting through the last 10 km and dragging yourself to the finish line. Treat your stomach like your muscles — train it, adapt it, and it will carry you far.
