The Principles of Tapering and Carb-Loading
The week before a marathon is known as the taper period, where training volume decreases significantly to allow the body to recover and prepare for race day. This is the ideal time to implement a strategic carbohydrate-loading plan, which is essential for endurance events lasting longer than 90 minutes. The goal isn't simply to eat more food, but to strategically shift your macronutrient ratio to prioritize carbohydrates over fat and protein. This ensures your muscle and liver glycogen stores—the primary fuel source for a marathon—are completely topped off. Research has shown that a depletion phase (intentionally cutting carbs) is not necessary and can even be detrimental. The modern approach focuses on a direct, high-carbohydrate intake for 2 to 3 days before the race.
A Day-by-Day Marathon Week Nutrition Guide
Monday - Wednesday: The Initial Taper Phase
During the initial days of your taper, your training load is decreasing, but your nutrition should remain relatively consistent with your higher-mileage weeks. Focus on balanced meals that include healthy carbohydrates, lean protein, and fats. This helps your body recover from peak training and prepares it for the carb-loading to come. If your appetite decreases with reduced activity, ensure you're still eating enough calories to avoid under-fueling. A daily fluid intake of 2-3 liters is a good baseline, increasing based on activity and temperature.
Thursday - Friday: The Main Carb-Load
This is the critical 48-72 hour window for carbohydrate loading. The objective is to increase your carbohydrate intake to 7-12 grams per kilogram of body weight per day. For a 70kg runner, this means consuming 490-840g of carbs daily. The key is to achieve this by adjusting your macronutrients, not by drastically increasing your overall calorie intake. Reduce your fat and fiber intake to make room for the extra carbs and prevent gastrointestinal issues.
- Shift your focus: Swap high-fiber whole grains for their white or low-fiber counterparts (e.g., white pasta instead of whole wheat pasta, white rice instead of brown rice).
- Eat frequently: Instead of relying on three huge meals, eat smaller, more frequent meals and snacks throughout the day to make the high carb volume more manageable.
- Incorporate carb-rich fluids: Use sports drinks, fruit juices, or a carb-specific drink mix to supplement your food intake without feeling overly full.
Saturday: The Day Before the Race
On the day before the marathon, the goal is to consolidate your glycogen stores without overloading your digestive system. Your biggest meal should be lunch, not dinner, to allow plenty of time for digestion. For dinner, choose a light, low-fiber, high-carb meal that you have practiced with during training. Avoid spicy, fatty, or high-fiber foods that could cause stomach distress. Continue to sip on water and electrolyte drinks, but avoid chugging large quantities.
A Comparison of Macronutrient Strategies
| Macronutrient | During Peak Training | During Carb-Loading (2-3 days pre-race) |
|---|---|---|
| Carbohydrates | 5-7g per kg body weight per day | 7-12g per kg body weight per day |
| Protein | Balanced with carbs and fat | Reduced slightly to make room for carbs |
| Fat | Balanced with carbs and protein | Significantly reduced to make room for carbs |
| Fiber | Normal healthy intake (whole grains, veggies) | Lowered to minimize GI distress |
The Final 24 Hours: Race Morning
On race morning, nerves can suppress appetite, but eating a small, high-carb, low-fiber breakfast is essential. Have this meal 2-4 hours before the race start, sticking to foods you've tested in training. Top off your glycogen stores with a small, simple carb snack (like a gel or banana) 30-60 minutes before the starting gun. Continue to sip fluids, but avoid over-hydrating, aiming for 150-250ml of fluid in the final 15 minutes before the race. This is not the time to experiment with new foods or large quantities of caffeine.
Conclusion
Your fueling strategy in the week before a marathon is a pivotal aspect of race-day success, not just an afterthought. By intelligently adjusting your intake to prioritize carbohydrates and hydration as your training tapers, you can maximize your energy reserves and minimize the risk of hitting the wall. Trust the process, stick to foods you know, and pay close attention to your body's signals. Proper fueling is the final piece of your months-long training puzzle, ensuring you cross the finish line feeling strong and accomplished.
