Understanding Carb Loading
Carbohydrate loading is a nutritional strategy for endurance athletes to maximize glycogen storage in their muscles and liver. Glycogen, a stored form of glucose, is the primary fuel for moderate to high-intensity exercise. For long runs and races over 90 minutes, your glycogen reserves are often not enough, which leads to fatigue. Increasing carbohydrate intake and decreasing training volume (tapering) helps to maximize these fuel stores, providing energy to finish strong.
Modern vs. Classic Carb Loading
Classic carb loading involved a glycogen depletion phase with low-carb diet before a high-carb diet. Current research shows this depletion phase is unnecessary. The current approach is more straightforward:
- Gradual Increase: Increase carbohydrate intake to 8-12 grams per kilogram of body weight per day in the 2-3 days before your run.
- Simultaneous Taper: This loading period should coincide with the tapering phase, where you reduce your mileage and intensity. This helps muscles absorb and store the excess carbohydrates.
Your 2-3 Day Carb Loading Plan
Days 2-3 Before Your Run:
- Prioritize Carbohydrates: Aim for 8-12g of carbohydrates per kg of body weight. For a 70kg runner, this is 560-840g of carbs daily.
- Reduce Fat and Fiber: Reduce fat and fiber intake. High-fiber foods can cause gastrointestinal distress.
- Stay Hydrated: Drink plenty of fluids, as water is essential for storing glycogen.
- Spread Your Intake: Eat smaller, more frequent meals and snacks.
The Night Before:
- Familiar Meal: Eat a familiar, carbohydrate-rich dinner that you tolerate well. Avoid new or spicy foods.
- Moderate Portion: Avoid overeating, which can disrupt sleep.
Race Morning (2-4 hours before start):
- Top Up Liver Stores: Have a light, easily digestible, carb-rich breakfast to replenish liver glycogen stores, which are depleted overnight. Examples include a bagel with jam, oatmeal, or a banana.
- Avoid High Fiber: Stick to refined, simple carbs to ensure quick digestion and minimize risk of GI issues.
- Hydrate: Continue sipping water or a sports drink.
Food Choices for Carb Loading
Focus on easily digestible, high-carb, low-fiber foods. Here is a table to guide your selections:
| Good Choices | Limit or Avoid |
|---|---|
| White pasta | Whole wheat pasta |
| White rice | Brown rice, wild rice |
| White bread, bagels | Whole grain breads |
| Oatmeal (instant) | High-fiber cereals, granola |
| Potatoes (peeled) | Sweet potatoes (high fiber), potato skins |
| Bananas, melons, fruit juices | High-fiber fruits like apples, berries |
| Pancakes, waffles, syrup | Muffins with nuts or bran |
| Low-fiber crackers, pretzels | High-fiber crackers |
| Sports drinks, energy gels | Caffeinated sodas, excessive caffeine |
Common Carb Loading Mistakes
- Waiting Until the Night Before: Carb loading requires a 2-3 day window.
- Not Eating Enough Carbs: Many athletes underestimate carbohydrate needs. Consuming sufficient liquids like sports drinks and juices can help.
- Overdoing Fiber and Fat: These nutrients can cause digestive issues. They should be minimized during the final 24-48 hours.
- Experimenting with New Foods: The days before a run are not the time to introduce new menu items.
- Forgetting Hydration: Inadequate fluid intake can hinder glycogen storage.
- Fearing Weight Gain: A temporary gain of 1-2kg is normal as a sign of glycogen and water storage.
For more detailed nutritional information, including during-race fueling, consider resources like the Sports Dietitians Australia.
Conclusion
Proper carb loading requires a strategic approach. Start 2-3 days before your run, focus on low-fiber carbohydrates, and stay hydrated to maximize glycogen reserves. Avoid a last-minute strategy, high-fat meals, and unfamiliar foods. A practiced approach ensures the body is fueled to perform at its best.
