What to Eat a Week Out from a Marathon for Peak Performance

December 21, 2025 •

4 min read

Studies show that effective carb-loading can significantly boost marathon performance and endurance. To understand what to eat a week out from a marathon, you must shift your focus from training fuel to race-day glycogen storage, with a clear strategy for the final seven days.

Quick Summary

The final week before a marathon requires a strategic nutrition plan focused on maximizing glycogen stores. The diet shifts to higher carbohydrate intake while minimizing fat, protein, and fiber to ensure optimal energy availability and prevent gastrointestinal issues on race day.

Key Points

Prioritize Carbs: Gradually increase carbohydrate intake over the final 72 hours, aiming for a high proportion of your total calories.
Reduce Fiber and Fat: Minimize high-fiber foods, fats, and excessive protein in the final 48 hours to avoid GI distress and prioritize carbohydrate storage.
Stay Hydrated: Focus on consistent hydration throughout the week, using water and electrolyte drinks to stay topped up.
No New Foods: Stick to familiar, tested foods during the race week to prevent any unpleasant stomach surprises on race day.
Practice Makes Perfect: Implement a race-day nutrition rehearsal during your longest training runs to fine-tune your strategy.
Last Big Meal: Eat your main carb-heavy meal two nights before the race, not the night immediately preceding it, to prevent a bloated feeling.
Embrace Water Weight: A small weight gain from carb-loading is normal and beneficial, as glycogen is stored with water.
Listen to Your Body: Adjust your intake based on what feels right for you, as every runner is different.

The Tapering Diet: More Carbs, Less Intensity

During the final week before your marathon, your training intensity and volume decrease significantly. This period, known as the taper, allows your body to recover, repair muscles, and build maximum energy reserves. Your nutrition strategy during this week must adapt to support these goals. The overall calorie intake should remain relatively consistent with your higher-mileage training weeks to ensure you have enough energy to fully replenish your glycogen stores. Rather than simply eating more, the key is to shift the proportion of your macronutrients. This means increasing your carbohydrate intake while deliberately reducing your consumption of fats and fiber.

Carb-Loading: The Fueling Strategy for Race Week

Carb-loading is the strategic process of eating and drinking more carbohydrates than normal in the final days before an endurance event. The excess carbohydrates are stored in your muscles and liver as glycogen, providing the primary fuel source for your race. The modern approach to carb-loading, unlike older methods, does not require an initial "depletion" phase. You simply increase your carbohydrate consumption in the 2–3 days immediately preceding the race. For a 70kg runner, this could mean targeting 10 grams of carbohydrate per kilogram of body weight per day. Since your body also stores water with glycogen, expect a slight, temporary weight gain. This is normal and beneficial for hydration.

High-Carb, Low-Fiber Food List

In the 48 hours before the race, you'll want to choose easily digestible, lower-fiber carbohydrate sources to avoid gastrointestinal issues.

White Bread and Bagels: Easy on the stomach and provide a dense source of carbs.
White Rice and Pasta: Simple pasta with a tomato-based sauce is a classic pre-race meal.
Oats: Rolled oats or rice krispies are excellent, low-fiber options.
Potatoes: Baked, boiled, or mashed potatoes offer a clean, starchy carbohydrate boost.
Bananas: An easily digestible source of carbs and potassium, a key electrolyte.
Energy Drinks and Gels: Can supplement your carb intake without adding bulk.
Fruit Juices: Provides simple sugars for a quick carb top-up.

Foods to Avoid During Race Week

Just as important as knowing what to eat is knowing what to avoid. The final week is not the time to experiment with new foods. Your gut needs consistency to perform its best on race day.

High-Fiber Foods: Reduce or eliminate whole grains, high-fiber cereals, and large quantities of fibrous vegetables and legumes to prevent bloating and mid-race pit stops.
Spicy Foods: Anything that can cause stomach upset should be off the menu.
High-Fat Foods: Heavy, fried, or overly oily foods take longer to digest and can leave you feeling sluggish. Swap fries for a baked potato.
Excessive Protein: While still important for recovery, protein intake should be moderated in the final 48 hours to prioritize carbohydrate loading.
Alcohol: This can disrupt sleep, dehydrate you, and impair glycogen storage.

Comparison Table: Taper vs. Training Diet

This table highlights the dietary shifts needed during the critical final week.


Aspect	During Training	Final Taper Week	Final 48 Hours	The Night Before	The Morning Of
Carbohydrates	50-60% of total calories	60-70% of total calories	Up to 75%+, lower fiber	High-carb, moderate protein	High-carb, low-fat/fiber
Fiber	Normal to high	Moderate	Low, easily digested carbs	Minimal	Minimal
Fat	Balanced healthy fats	Reduced	Minimal	Minimal	Minimal
Protein	Higher for muscle repair	Moderated	Moderated	Moderate, lean source	Moderate, lean source
Goal	Replenish & recover	Replenish glycogen stores	Top off glycogen stores	Easy digestion	Last-minute top-up

Hydration: Your Week-Long Focus

Starting a marathon dehydrated can significantly impact performance. Your hydration strategy should begin days, not hours, before the race. Focus on consistent fluid intake throughout the week, aiming for a pale, light yellow urine color as an indicator of proper hydration. For longer runs or hot conditions, consider adding electrolytes to your water or using sports drinks. The final two days should involve slightly increased fluid intake, but avoid over-drinking, which can lead to low sodium levels (hyponatremia).

The Final 48 Hours: Countdown to the Start Line

As you get closer to race day, fine-tune your meals even more. A helpful strategy is to make your largest carb-heavy meal two nights before the race (e.g., Friday night for a Sunday race). This provides ample time for digestion and storage, avoiding the bloated feeling on race morning. The final night's meal should be lighter but still carbohydrate-rich. Think simple pasta with a mild sauce or a large baked potato with cheese. For the race-day breakfast, eat what you've practiced with and know works for you, 2-4 hours before the start. Options like a bagel with a little peanut butter and banana or oatmeal with honey and fruit are great choices.

Conclusion: Stick to the Plan and Trust Your Gut

Proper race week nutrition is the final piece of the training puzzle. By strategically increasing carbohydrates, staying hydrated, and avoiding new or high-fiber foods, you ensure your body is fully fueled and ready for the challenge. The most important rule is to stick to foods you've tested during your long runs, eliminating any last-minute surprises. This mindful approach to fueling, coupled with the reduced training load, will have you feeling strong and confident at the start line, with the energy reserves needed to cross the finish. For more detailed nutritional guidance, consider visiting the resources at a site like Johns Hopkins Medicine to consult with a registered dietitian.

A Final Word on Hydration and Digestion

Remember that while carb-loading can temporarily increase your weight due to water retention, this is a positive sign that your fuel tanks are full. Also, for those with sensitive digestive systems, reducing fiber even more aggressively in the final days is a smart play to minimize any risk of issues during the race.

Frequently Asked Questions

You should begin carb-loading, which involves increasing your carbohydrate intake, approximately 2 to 3 days before the marathon. This is often during the final taper phase of your training.

Focus on easily digestible, lower-fiber carbohydrates such as white bread, white rice, pasta with a simple tomato sauce, baked potatoes, and oatmeal.

In the week leading up to the race, avoid new foods, high-fiber options (like excessive whole grains and legumes), spicy foods, and high-fat foods to prevent gastrointestinal upset.

Hydrate consistently throughout the week with plenty of water and consider adding electrolytes. A good indicator is pale, light yellow urine. Avoid excessive drinking to prevent low sodium levels.

No, it is generally recommended to have your main carb-heavy meal two nights before the race. The night before should be a lighter, but still carbohydrate-rich, meal to prevent feeling heavy or bloated.

Yes, it is normal to gain a little weight. This is because every gram of glycogen stored in your muscles is also stored with several grams of water, which is beneficial for hydration and energy.

Eat a familiar, high-carbohydrate, low-fiber breakfast 2 to 4 hours before the race. Good options include a bagel with a small amount of peanut butter and banana, or oatmeal.

Sticking to foods you've tested in training minimizes the risk of unexpected digestive issues on race day. Your gut, like your muscles, needs to be trained for race conditions.