Marathon Nutrition Guide
Personalized nutrition and hydration strategies for optimal marathon performance.
Runner Profile
Pre-Race Nutrition Plan
Carb-Loading (3 Days Before)
560-840g
of carbs per day
- Focus on easily digestible carbs (rice, pasta, potatoes)
- Reduce fiber intake gradually
- Maintain adequate hydration with electrolytes
- Moderate protein intake (1.2-1.6g/kg body weight)
- Limit fat to make room for carbohydrates
Day Before Race
- Breakfast: Carb-rich breakfast (oatmeal, toast, fruit)
- Lunch: Moderate-sized meal with plenty of carbs, some protein
- Dinner: Early, carb-heavy dinner (4-5 hours before bed)
- Hydration: Drink 500-750ml extra water with electrolytes
- Evening snack: Small carb-rich snack if hungry
- Avoid alcohol and minimize caffeine
Pre-Race Breakfast
70-280g
of carbs 2-4 hours before
- Eat 2-4 hours before race start
- Keep fat, protein, and fiber low to moderate
- Sample meals:
- Oatmeal with banana and honey
- Bagel with jam and small amount of nut butter
- White rice with small amount of protein
- Sports drink + energy/granola bar
Race Morning Timeline
- 4 hours before: Main pre-race meal
- 2 hours before: Drink 5-7ml/kg of water or sports drink
- 60-90 min before: Optional small carb snack (banana, energy bar)
- 30-60 min before: Sip water as needed
- 15-30 min before: Optional carb mouth rinse or small energy gel
- Pre-start: Final hydration sips
During Race Fueling Strategy
Carbohydrate Intake
45-60g per hour
optimal intake
- Start fueling early (30-45 minutes into the race)
- Consume carbs at regular intervals (every 15-20 min)
- Mix carbohydrate sources for better absorption:
- Energy gels (25-30g carbs per gel)
- Sports drinks (30-60g carbs per 500ml)
- Chews/blocks (5-10g carbs per piece)
- Whole foods (banana, dates, etc. for slower paces)
Hydration Strategy
600-800ml per hour
fluid needs
- Start race well-hydrated but not overhydrated
- Drink to thirst, aiming for consistent small amounts
- Alternate between water and electrolyte drinks
- Practice drinking while running in training
- Adjust intake based on temperature:
- Cool weather: Lower end of range
- Hot weather: Upper end of range
Electrolytes
- Consuming 300-600mg sodium per hour is recommended
- Sources of electrolytes:
- Sports drinks
- Electrolyte tablets/capsules
- Salt packets
- Electrolyte-enhanced gels
- Heavy sweaters should aim for the higher end of sodium intake
- Watch for signs of imbalance: nausea, confusion, muscle cramping
Sample Fueling Plan
For a Sub-4:00 marathon:
- Start to 1 hour: 1 gel at 30-45 min + water/sports drink at aid stations
- 1-2 hours: Gel every 30-45 min + 120-180ml fluid every 15-20 min
- 2+ hours: Continue same pattern, possibly increasing frequency of carbs
Important Notes:
- PRACTICE YOUR RACE DAY NUTRITION DURING TRAINING!
- Never try new products or strategies on race day
- Train your gut by practicing your fueling strategy during long runs
- Have a backup plan if your primary fueling choice isn't available
- Adjust based on how you feel during the race