How to Properly Carb Load for a Race?

January 5, 2026 •

4 min read

Research shows that effective carbohydrate loading can boost performance by up to 2-3% in endurance events lasting over 90 minutes. A strategic pre-race nutrition plan is vital, so understanding how to properly carb load for a race is a crucial skill for any serious athlete. This process involves more than just eating a huge pasta dinner the night before; it's a science-backed strategy to top off your body's energy reserves.

Quick Summary

Carb loading is a strategic nutritional approach that involves increasing carbohydrate intake while tapering training in the 2-3 days before an endurance event. It is designed to maximize muscle glycogen stores, providing a readily available fuel source to delay fatigue and enhance race-day performance.

Key Points

Timing is Key: Start your carb load 2-3 days before the race, not just the night before, to fully saturate muscle glycogen stores.
Calculate Your Needs: Aim for 8-12 grams of carbohydrates per kilogram of body weight per day during the loading phase.
Prioritize Low-Fiber Carbs: Choose white versions of bread, pasta, and rice over whole-grain to reduce fiber intake and minimize digestive issues.
Reduce Fat and Protein: Decrease your fat and protein consumption to make room for the higher carbohydrate intake without feeling overly full.
Stay Hydrated: Increase your fluid intake, as extra water is stored with the glycogen, which is beneficial for performance.
Practice Your Plan: Test your carb-loading strategy during training runs to ensure your body tolerates the specific foods you plan to eat.

Understanding the Science of Carbohydrate Loading

Carbohydrate loading, often referred to as 'carb loading,' is a strategic dietary practice for endurance athletes. The goal is to maximize the storage of glycogen in your muscles and liver. Glycogen is a stored form of glucose, your body's primary energy source during high-intensity, long-duration exercise. The process combines an increase in carbohydrate intake with a reduction in training volume, known as tapering, to allow the body to save up its fuel. For every gram of glycogen stored, your body also stores about three grams of water, which is why temporary weight gain is normal and beneficial for hydration.

The Modern Carb-Loading Approach

The old-school method of carb-loading involved a glycogen depletion phase, where athletes would significantly reduce carbohydrate intake to force the body to store more later on. However, modern sports nutrition research has shown that this is not necessary. A simpler, more effective method involves a 2-3 day period of high carbohydrate intake combined with training taper. This is less stressful on the body and gut, reducing the risk of illness or injury before the race.

Planning Your Carb-Loading Phase

The duration and intensity of your race determine if and how you should carb load. For events under 90 minutes, a single high-carb meal the night before is sufficient. For longer events like marathons, a 2-3 day loading window is recommended. The amount of carbohydrates needed depends on your body weight. A typical recommendation is 8-12 grams of carbohydrates per kilogram of body weight per day. For a 70kg runner, this means consuming 560-840 grams of carbs daily. Spreading this intake throughout the day with 3 main meals and 2-3 high-carb snacks is key to success.

High-Carbohydrate Food Choices

When carb-loading, focus on high-carb, low-fiber, and moderate-protein and fat options. Limiting fiber prevents gastrointestinal distress on race day. Here are some ideal food choices for your carb-loading meals and snacks:

Breakfast: Oatmeal, bagels with jam or honey, pancakes with syrup.
Lunch/Dinner: Pasta with low-fat sauce, white rice with lean chicken or fish, homemade pizza on white dough.
Snacks: Pretzels, fruit juices, low-fiber cereal, bananas, energy bars.
Liquid Carbs: Sports drinks, fruit juice, and smoothies are excellent ways to consume extra carbs without feeling too full.

Comparison of High-Carb Food Sources


Food Item	Carbohydrate Type	Fiber Content	Digestibility	Best For...
White Rice	Simple/Starch	Low	High	Pre-race meals, especially for sensitive stomachs
White Pasta	Simple/Starch	Low	High	Classic, easily digested dinner option
Oats	Complex/Starch	Moderate	Moderate	Training, race morning (test beforehand!)
Bananas	Simple/Sugar	Low	High	Portable, fast-acting snack
Sports Drink	Simple/Sugar	None	Very High	Liquid calories for topping off glycogen
Sweet Potato	Complex/Starch	High	Moderate	Earlier in the week, can cause GI issues closer to race day

Practical Steps and Common Mistakes

Your Carb-Loading Checklist

Calculate Your Target: Determine your daily carb goal based on body weight (e.g., 8-12g/kg).
Plan Your Meals: Structure your days with 3 main high-carb meals and 2-3 high-carb snacks to meet your target.
Choose Low-Fiber Carbs: Switch from whole-grain to white versions of bread, pasta, and rice to minimize fiber intake and reduce GI upset.
Stay Hydrated: Glycogen storage requires water, so increase your fluid intake alongside your carbs. Monitor your urine color; it should be a pale yellow.
Practice in Training: Never try a new fueling strategy on race day. Practice your carb-loading plan before long training runs to see what works for your body.

Common Mistakes to Avoid

Overeating: Carb loading is not an excuse for an eating binge. The focus is on increased carbohydrate proportion, not overall caloric excess.
Loading with Too Much Fiber or Fat: High fiber and fat content can cause bloating, digestive issues, and make it difficult to consume enough carbs.
Waiting Until the Last Night: A single huge pasta meal the night before is inefficient. Spread your carb intake over 2-3 days for maximum glycogen storage.
Ignoring Weight Gain: Expect to gain 1-2kg of temporary water weight. This is a sign of successful glycogen storage, not fat gain.

Conclusion: Fuel Your Performance

Carbohydrate loading is a proven strategy for improving endurance performance and delaying the onset of fatigue. By systematically increasing your carbohydrate intake over the 2-3 days leading up to your race while tapering your training, you can ensure your body's fuel tank is completely topped off. Focus on familiar, low-fiber, high-carb foods and stay well-hydrated throughout the process. Practice your fueling strategy during training to avoid surprises on race day and confidently stride towards your personal best.

Visit a reputable sports nutrition resource for more fueling strategies.

Frequently Asked Questions

No, while some athletes follow a high-fat diet for daily training, carb loading remains the superior strategy for maximizing glycogen stores and improving performance in endurance events over 90 minutes.

Carb loading is generally unnecessary for shorter races like a 5k or 10k. A balanced diet and a solid meal a few hours before the race are usually sufficient.

For optimal digestion and energy availability, consume your final main meal 3-4 hours before the race. Some athletes also tolerate a small, easily-digestible snack closer to the start time.

No, the temporary weight gain experienced during carb loading is due to water retention associated with glycogen storage, not fat. This weight will be utilized and shed during your race.

On race morning, stick to a breakfast rich in simple, low-fiber carbs that you have practiced with. Good options include a bagel with jam, a banana, or some oatmeal.

No, a single, excessively large meal can cause digestive upset and bloating. It is more effective to spread your increased carb intake across 2-3 days with multiple meals and snacks.

No, modern research has shown that the depletion phase, which involved restricting carbs for several days, is unnecessary and can be stressful on the body. A simple taper and load is enough.

If you experience bloating, ensure you are drinking enough fluids and prioritize low-fiber carbs. Test your meal plan during training to identify foods that might cause discomfort.