Nutrition Diet: What to eat a week before a big race?

October 25, 2025 •

3 min read

Studies show that proper carbohydrate loading can boost your body's energy stores by up to 30% or more, significantly enhancing endurance during a long race. To maximize your performance and avoid digestive issues, knowing what to eat a week before a big race is crucial for every runner.

Quick Summary

A runner's pre-race week involves a strategic nutrition shift: increase carbohydrate intake while reducing fat, protein, and fiber. Focus on easily digestible, familiar foods and consistent hydration, practicing your plan during training to prevent race-day stomach issues.

Key Points

Start Early: Begin carb-loading 2-3 days before the race, not just the night before, to effectively maximize glycogen stores.
Shift Macronutrients: During the carb-loading phase, increase the proportion of carbohydrates while slightly decreasing fat and protein to avoid over-consuming calories.
Go Low-Fiber: In the final 48-72 hours, switch to low-fiber carb sources like white rice and white bread to prevent gastrointestinal distress during the race.
Stay Hydrated: Consistently drink fluids throughout the week, and consider adding electrolytes, especially if you're a heavy sweater or the weather is hot.
Stick to Familiar Foods: Avoid experimenting with new foods or supplements in the final week to prevent unexpected digestive issues on race day.
Don't Overeat: Carb-loading is about strategic food choices, not gorging. Overeating can lead to sluggishness and discomfort.
Practice Your Plan: Use your long training runs as a chance to practice your hydration and nutrition strategy, including the specific foods and supplements you'll use on race day.

The Final Countdown: Your Week-Before Race Nutrition Plan

The week leading up to a major race, also known as the taper week, requires a focused nutritional strategy to ensure your body is adequately fueled. The primary goal is to maximize the storage of muscle glycogen, which is the key energy source for endurance activities. While consistent healthy eating is always important, this final week involves specific adjustments to your diet and hydration.

The Importance of Carb-Loading (And How to Do It Right)

Carb-loading is beneficial for endurance events lasting over 90 minutes. The current approach involves gradually increasing carbohydrate intake over 2 to 3 days while reducing training volume, which allows for optimal glycogen storage without discomfort.

Timing: Start increasing your carbohydrate intake 2-3 days before the race. Eating smaller, more frequent meals can be helpful during the taper when appetite may decrease.
Macronutrient Balance: Aim for 8 to 12 grams of carbohydrates per kilogram of body weight daily during the carb-loading period. Slightly reduce fat and protein intake to manage total calorie consumption.
Lower Fiber: In the final 2-3 days before the race, switch to lower-fiber versions of carbohydrates to help prevent potential gastrointestinal issues during the event.

Timing and Food Choices: A Day-by-Day Breakdown

Days 7-4 Before the Race: Focus on a balanced diet with complex carbohydrates, lean protein, and healthy fats as training volume decreases. Include whole grains, starchy vegetables, and lean protein sources.

Days 3-2 Before the Race: Begin increasing carbohydrate intake and reducing fiber, fat, and protein. Choose foods like white toast, low-fiber cereal, white rice, pasta with simple sauces, bananas, applesauce, pretzels, and plain bagels.

The Day Before the Race: Eat familiar, easily digestible meals. Avoid heavy or large meals, especially in the evening. Maintain consistent hydration.

Comparison Table: High-Fiber vs. Low-Fiber Carbs


Food Type	High-Fiber (Avoid closer to race)	Low-Fiber (Focus on days 3-2)
Grains	Whole wheat bread, oatmeal, brown rice	White bread, low-fiber cereal, white rice, refined pasta
Vegetables	Broccoli, cauliflower, lentils, beans	Skinned potatoes, cooked carrots, small amounts of green beans
Fruits	Apples, pears, raspberries (with skin)	Bananas, applesauce, fruit juices, dried fruit in moderation
Snacks	High-fiber bars, nuts, seeds	Pretzels, plain bagels, energy gels, sports drinks

Hydration: More Than Just Water

Proper hydration throughout the week is essential for optimal race performance.

Electrolyte Balance: Consider incorporating electrolyte drinks in the final days, especially in warm conditions or if you sweat heavily, to help your body retain fluids. Avoid consuming excessive plain water, which can dilute sodium levels.
Consistent Intake: Sip fluids regularly throughout the week. On race morning, a common guideline is about 16 ounces two hours before the start and 6-8 ounces 15 minutes prior.
Practice: Use long training runs to test your hydration strategy and the products you plan to use on race day to ensure they don't cause stomach upset.

Foods to Embrace and Foods to Avoid

Embrace:

Complex carbs like rice, pasta, and potatoes early in the week.
Simple carbs such as bagels, bananas, and low-fiber cereals closer to race day.
Lean protein for muscle repair, in smaller amounts during carb-loading.
Electrolytes via sports drinks or tabs.
Familiar foods you have eaten before.

Avoid:

High-fiber foods in the final 2-3 days.
High-fat, fried, or spicy foods, which can cause digestive issues.
Excessive caffeine and alcohol, which can lead to dehydration.

Conclusion: Trusting Your Taper and Your Gut

A strategic nutrition plan in the week before a big race complements your training by ensuring your energy stores are maximized. Carb-loading involves intentional eating, focusing on easily digestible, lower-fiber carbohydrates in the final days alongside consistent hydration. Practicing your nutrition strategy during training is key to avoiding race-day surprises. By following these guidelines, you can approach the starting line feeling well-prepared and fueled for success.

For more expert advice on nutrition for runners, visit REI's Expert Advice on Running Nutrition.

Frequently Asked Questions

No, carb-loading is generally unnecessary for shorter races like a 5K (less than 90 minutes). Your body has enough existing glycogen stores to fuel these efforts. Focus instead on a balanced diet and good hydration throughout the week.

The evening before the race, eat a familiar, moderate-sized meal rich in easy-to-digest carbohydrates and a small amount of lean protein. White pasta with a simple sauce, or white rice with grilled chicken, are common choices. Eat early to allow for proper digestion before sleep.

Good low-fiber carbohydrate options include white rice, white pasta, plain bagels, white bread, instant mashed potatoes, skinned potatoes, fruit juices, applesauce, and pretzels.

Eat a light, carb-rich, and easy-to-digest breakfast 2-4 hours before the race. Examples include oatmeal with a banana and a little honey, a bagel with a small amount of nut butter, or toast with jam.

Reducing fiber intake in the final 2-3 days helps minimize digestive issues like bloating, gas, and an urgent need for a bathroom break, which can be problematic during a race.

If you are a regular coffee drinker and your body is accustomed to it, a small amount of coffee might be okay. However, be cautious as caffeine can stimulate the GI tract and potentially cause stomach upset. Avoid trying excessive amounts or drinking it for the first time on race day.

A simple way to check your hydration is by monitoring the color of your urine. It should be a pale, straw-like color. Dark yellow urine can indicate dehydration. Additionally, consider practicing a sweat test during training to estimate your fluid loss.