A significant shift in sports nutrition, dubbed the “high-carb fueling revolution,” is enabling endurance athletes to break long-standing records. Top performers like cyclist Tadej Pogačar and ultra-runner Kilian Jornet are now consuming upwards of 120 grams of carbohydrates per hour—an amount previously considered impossible and detrimental. This strategy allows them to maintain high performance, reduce muscle damage, and recover faster.
The Science: From 60g to 120g Per Hour
For decades, sports nutrition guidelines capped carb intake at 30-60g per hour, based on the gut’s limited ability to absorb glucose through a single pathway. Pushing past this limit often led to gastrointestinal (GI) distress. The breakthrough came with the discovery that the gut uses two different transporters: one for glucose and another for fructose. By combining these two types of carbs, athletes can bypass the old ceiling. Modern research confirms that fueling with a glucose-fructose mix allows the body to absorb and utilize up to 120g of carbs per hour or more. Studies show this high intake leads to less muscle damage, lower perceived effort, and improved recovery, enabling higher quality training.
The Biggest Mistake: Under-fueling Your Training
A common mistake among endurance athletes is under-fueling, both in races and during training. Many, including the video’s host in his elite career, have operated under the false belief that training with minimal fuel (“training low”) forces beneficial adaptations and builds toughness. However, the science indicates the opposite. Fueling properly during hard and long workouts allows an athlete to train at a higher intensity and quality. Furthermore, it significantly speeds up recovery, meaning you can handle more training volume and be ready for your next key session sooner. Failing to practice fueling at race pace is another critical error, as the gut needs to be trained to handle high carb loads during intense effort to avoid race-day stomach issues.
Practical Application and Gut Training
To safely and effectively implement a high-carb strategy, athletes should follow a strategic approach. High-carb fueling is not necessary for short, easy runs but is a game-changer for key workouts (long runs, hard intervals) and races. The key is to “train your gut.” Start with a manageable amount, like 40-60g per hour during key sessions, and gradually increase the intake week by week. Just like muscles, the digestive system adapts by increasing the number of carb transporters, improving tolerance and reducing the risk of GI problems. The specific products used are less important than ensuring they contain a mix of glucose and fructose to maximize absorption.
Mentoring question
Reflecting on your own training habits, do you treat fueling as a critical component of your workouts, or is it an afterthought reserved only for race day?
Source: https://youtube.com/watch?v=fXfoyz7N8EQ&si=3-mhTflYZTiv887B
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