Does Eating Carbs Before a Race Help You Win?

December 12, 2025 •

2 min read

Research suggests that increasing carbohydrate intake before prolonged endurance events can boost performance. This approach, known as carbohydrate loading, addresses the question: does eating carbs before a race help? The answer is generally yes for longer distances, though the strategy varies depending on race length.

Quick Summary

Carb loading increases the body's stored energy (glycogen) to fuel endurance efforts over 90 minutes. A planned increase in carbohydrates, particularly in the 2-3 days leading up to a race, is a key nutritional strategy to prevent fatigue.

Key Points

Strategic Fueling: Eating carbs before a race maximizes your body's energy reserves, especially for events longer than 90 minutes.
Glycogen Stores: Carbohydrates are stored as glycogen, used as fuel during endurance activities.
Timing is Key: Carb loading typically involves increasing intake over 2-3 days before the race.
Avoid GI Distress: Reduce high-fiber and high-fat foods before a race.
Practice Makes Perfect: Test your pre-race fueling strategy during training.
Race Day Top-Up: Have a light, digestible, carb-rich meal 1-4 hours before the race.

The Science of Carb Loading

Carbohydrates are the primary fuel source for endurance athletes. They are stored as glycogen in muscles and the liver. During extended, intense exercise, the body uses these glycogen stores for energy. Insufficient glycogen can lead to fatigue and performance decline. Carb loading aims to maximize these energy reserves.

Effective carb-loading methods often involve increasing carbohydrate consumption over a few days before an event, combined with reduced training (tapering). This can allow muscles to store more glycogen.

Executing a Successful Carb Load

Quantify Intake: Endurance athletes typically target a specific range of carbohydrates per kilogram of body weight per day in the 2-3 days before a race. Carbohydrates should represent a larger portion of total calories.
Select Appropriate Carbs: In the 1-2 days before the race, choose lower-fiber carbohydrate foods to minimize potential digestive issues.
Trial Your Plan: Practice your carb-loading and race-day meals during training sessions.

Pre-Race and Race-Day Fueling

Consuming a final meal before the race is important for topping off glycogen stores and should be eaten several hours beforehand for digestion. The ideal race-day breakfast is easy to digest, high in carbohydrates, low in fiber and fat, and uses familiar foods. A larger meal can be eaten further out, while a smaller snack is suitable closer to the start.


Meal Timing	Food Choices	Purpose
2-3 Days Pre-Race	Low-fiber carb sources (e.g., white rice, pasta, bagels, oats)	Maximizes muscle glycogen stores for long events.
The Night Before	Moderate, carb-focused meal (e.g., white pasta, lean protein); consume early	Supports glycogen stores without causing discomfort before sleep.
Race Morning (3+ hours)	Easily digestible carbs (e.g., oatmeal, bagel, banana)	Final top-up of glycogen; using practiced foods helps avoid GI issues.
30-60 Mins Before	Quick-absorbing carbs (e.g., energy gel, sports chews)	Provides an immediate energy source.

Is Carb Loading Always Needed?

Carb loading is highly beneficial for endurance events exceeding 90 minutes. However, it's generally not necessary for shorter races like a 5K or 10K, where typical glycogen levels are usually adequate. For shorter distances, focus on a balanced diet and a suitable pre-race meal.

The Takeaway: Fueling Smart for Performance

Eating carbs before a race is a key strategy for endurance athletes competing in events over 90 minutes. Implementing proper carb-loading days before and consuming a strategic pre-race meal optimizes energy reserves. Practicing your nutrition during training is crucial to determine personal tolerance and prevent digestive upset on race day. Seeking advice from a sports dietitian can offer tailored recommendations.

Conclusion

Consuming carbohydrates strategically before a race is essential for endurance athletes participating in events lasting over 90 minutes. Focused carb loading in the days preceding the event and a well-timed pre-race meal enhance muscle glycogen stores, helping to delay fatigue. Practicing fueling during training and opting for low-fiber, familiar carbohydrates reduces the likelihood of stomach issues, contributing to a more successful race experience.

Frequently Asked Questions

Carb loading is a nutrition plan where endurance athletes consume high carbohydrates over a few days before an event to maximize glycogen storage.

Carb loading isn't typically necessary for races under 90 minutes like a 5K or 10K; normal glycogen levels are usually enough.

The night before, eat a familiar, carb-heavy, low-fiber meal, such as white pasta or rice with lean protein.

Eat your race day breakfast 2-4 hours before the start to allow for digestion and energy use.

Good options include easy-to-digest, low-fiber foods like white pasta, rice, bagels, oats, and bananas, avoiding high-fiber or high-fat items.

A temporary weight gain of 1-2kg (2-4 lbs) is common due to water stored with glycogen, indicating successful fueling.

Yes, testing your carb-loading plan before long training runs helps identify which foods work best for you on race day.