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The Marathon Series with Tom Hamilton – Carb Loading

Published: 26 Jun 2023

Carb loading, or carbohydrate loading, is a widely practiced strategy that involves increasing carbohydrate intake before an endurance event. By stocking up on glycogen, the primary fuel source for our muscles and liver, runners can improve their endurance and sustain performance for longer durations. In this blog post, we will explore the science behind carb loading and provide guidance on how to effectively implement this strategy for optimal results.

Understanding the Role of Glycogen

Glycogen is the stored form of glucose, which serves as the primary energy source during prolonged exercise. Our bodies can typically store around 90-120 minutes’ worth of glycogen. Once glycogen stores are depleted, the body turns to alternative fuel sources, such as fat. However, fat conversion is a slower process, leading to a significant decline in performance commonly referred to as “hitting the wall.” (note – there is some emerging evidence that high fat low carb diets may improve metabolic flexibility)

Carb Loading Protocol:

Thanks to Amy Stephens for this infographic. You can follow Amy here https://www.instagram.com/amystephensnutrition

To effectively carb load, follow this step-by-step protocol:

1. Seven Days Before the Race:

• Consume approximately 6-10 grams of carbohydrates per kilogram of body weight.
• Focus on complex carbohydrates such as whole grains, legumes, and starchy vegetables.

2. Day Before the Race:

• Increase carbohydrate intake to around 10-12 grams per kilogram of body weight.
• Incorporate carb-rich foods such as bread, pasta, rice, cereal, potatoes, and fruit into your meals.

3. Day of the Race:

• Consume a pre-race meal containing 2-3 grams of carbohydrates per kilogram of body weight, ideally 3-4 hours before the event.
• Stick to easily digestible carbs to avoid gastrointestinal discomfort.

Choosing the Right Carbohydrates:

• Complex Carbs: Emphasize whole grains, legumes, and starchy vegetables, as they provide sustained energy release.
• Simple Sugars: While not a large component of your regular diet, incorporating some simple sugars and refined grains during carb loading can be beneficial due to their quick digestion and immediate energy release. However, moderation is key to prevent stomach discomfort.

Carb loading is a scientifically supported strategy that can significantly enhance endurance performance by maximizing glycogen stores. By following the recommended protocol and choosing appropriate carbohydrate sources, runners can improve their energy availability and delay fatigue during endurance events. Remember, proper nutrition is just one aspect of a well-rounded training and preparation plan.