IM 70.3 Pre-Race 24-Hour Nutrition: A Carb-Loading Menu Without the Bloat

Core Goals for the 24 Hours Before the Race

An IM 70.3 (half ironman) takes 4–7 hours total, requiring you to push glycogen stores to 600–700 g (the average person has about 400–500 g). But eating the wrong things the day before can cause:

• Stomach bloating (high fiber)
• Nausea at the start (high fat)
• Too many bathroom trips (high protein)
• Dehydration (high-salt dry foods)

24-Hour Timeline

24 Hours Before the Race (D-1, 7:00 AM)

Breakfast: 2 slices of white toast + jam + banana + black coffee

• Carbs: 85 g
• Protein: 12 g
• Fat: 5 g
• Calories: 430 kcal

D-1, 10:00 AM

Snack: 1 white rice ball (tuna flavor) + 500 ml sports drink

• Carbs: 90 g
• Calories: 440 kcal

D-1, 12:30 PM

Lunch: 1.5 bowls of white rice + 100 g chicken breast + steamed egg + soy sauce

• Carbs: 120 g
• Protein: 30 g
• Fat: 8 g
• Calories: 680 kcal
• Avoid: leafy greens (high fiber), green salad, beans

D-1, 3:00 PM

Afternoon snack: 1 slice of white toast + honey + 1 banana + 500 ml sports drink

• Carbs: 95 g
• Calories: 430 kcal

D-1, 5:00 PM (14 Hours Before the Race)

Dinner (the most important meal): 2 bowls of white rice + 80 g grilled fish + miso soup (don’t eat the solids) + a small amount of pickled cucumber

• Carbs: 130 g
• Protein: 25 g
• Fat: 6 g
• Calories: 720 kcal
• Key point: Eat early, giving your stomach 14 hours to digest

D-1, 8:00 PM

Pre-bedtime snack: 1 slice of white toast + honey + 200 ml warm milk (if you tolerate it) or warm water

• Carbs: 50 g
• Calories: 280 kcal

Race Morning, 4:00 AM (3 Hours Before the Race)

Breakfast: 1 bowl of white rice porridge + 2 teaspoons of honey + half a banana

• Carbs: 80 g
• Calories: 340 kcal

60 Minutes Before the Race (6:00 AM)

400 ml sports drink + 1 energy gel

• Carbs: 50 g
• Calories: 200 kcal

24-Hour Total Intake

Foods to Avoid

Hydration Strategy

• Throughout D-1, drink 150–200 ml of water or sports drink every hour
• Cut back after 7:00 PM to avoid middle-of-the-night bathroom trips
• Check urine color: it should be light yellow, not clear (overhydrated) or dark yellow (dehydrated)

Extra Salt

Season D-1 meals slightly saltier, or take 2 extra salt tablets (adding +500 mg sodium total), which helps with fluid retention.

Conclusion

The core of IM 70.3 pre-race nutrition: focus on white foods (white rice, white toast, white rice porridge), eat early and in multiple small meals, so your glycogen stores are topped off while your stomach is emptied out.

Related Reading

• Carb-Loading Three Days Before a Race: A Complete Plan with a Real-World Example
• Sports Nutrition 3 Days Before an Olympic-Distance Triathlon: The Science of Carb Loading
• 70.3 Half-Ironman Finish Guide: Pacing Strategies for Middle-Distance Athletes
• 70.3 Race Day: A Timeline from Waking Up to Starting