120g of carbs per hour?! Pushing the Limits of Carb Fueling

Welcome to the first episode of Endurance Eats! I’m so excited to kick off this podcast with a fundamental but often misunderstood aspect of endurance nutrition: carbohydrate fueling during exercise. Specifically, this growing trend of endurance athletes fueling with 120 grams of carbs per hour?!

For endurance athletes, carbs are crucial, but it’s easy to wonder: how much do I need? When should I take it? And why does it matter? In this podcast episode, I’ll answer these questions, sharing evidence-based strategies and practical advice to help you fuel your workouts effectively and feel your best.

Why Carbohydrates Are Essential for Endurance Athletes

Carbohydrates are a primary energy source during long and intense activities. They provide fast, accessible fuel for muscles, helping sustain effort over extended periods. However, many athletes are under-fueling during workouts, relying on occasional gels or snacks that don’t supply enough carbs per hour to optimize performance.

Here are three key benefits of optimal carbohydrate fueling for endurance athletes:

1. Enhanced Performance: Adequate carbs improve endurance, translating to better training outcomes and faster progress.
2. Stable Energy Levels: Sufficient carbs prevent energy slumps, sugar cravings, and hunger dips, especially when training early in the day.
3. Improved Gut Tolerance: Regular carb fueling trains your gut, reducing the risk of gastrointestinal (GI) issues on race day.

Understanding Optimal Carbs Per Hour Fueling Rates

One of the biggest misconceptions is that fueling needs are based on calorie burn or body size. In reality, optimal carbohydrate intake depends on exercise duration and how much your gut can comfortably absorb. Studies show that our gut absorbs carbs at a similar rate regardless of body weight, so the recommendations are the same across various athlete builds.

Carbohydrate Intake Recommendations Based on Exercise Duration

• 30-75 Minutes: A small amount of fuel, around 20-30 grams of carbs, can help maintain performance, especially if the workout is intense. This is also a great opportunity to start training your gut.
• 75-150 Minutes: Aim for 30-60 grams of carbs per hour, with the upper end of this range ideal for workouts over 90 minutes.
• 150+ Minutes: Aim for up to 90 grams of carbs per hour. Some high-level athletes are even going with 120 grams, but gut tolerance is essential for this level.

The Science Behind Carb Ratios: Glucose and Fructose

To maximize carb absorption, endurance athletes should consider a mix of glucose and fructose in their fueling strategies. Here’s why:

Both glucose and fructose use different transport mechanisms in the gut. Think of glucose as taking the “bus” route and fructose as taking the “train” route. Because these pathways don’t compete with each other, combining them can increase the total amount of carbs absorbed per hour. The standard glucose-to-fructose ratio recommendation is 2:1 or 1:0.8, but the exact ratio can vary depending on individual tolerance.

Many athletes experiment with custom hydration mixes, balancing glucose and fructose sources like maltodextrin to fine-tune gut tolerance and performance. For a higher carb intake (90+ grams per hour), paying attention to this ratio can help optimize absorption and reduce GI distress.

Overcoming Common Fueling Challenges

Carb fueling can be challenging for a few reasons. Here are some tips to overcome the most common issues athletes face:

Training the Gut for High Carb Intake

Consuming large amounts of carbs without practice can lead to GI distress on race day. Start training your gut early by gradually increasing your intake during workouts. For example, if you’re targeting 90 grams per hour, try dividing it into three doses of 30 grams every 20 minutes. This approach can prevent overwhelming the gut and provide steady energy.

For more on exercise-induced GI distress, read here.

Dealing with Flavor Fatigue

Endurance fueling products are often sweet, which can lead to flavor fatigue. To make long sessions more enjoyable, consider rotating between sweet and salty options or opting for products with milder flavors. For example, some athletes use savory options like rice cakes, mild sports bars, or electrolyte mixes with a neutral taste to give their palate a break.

Fueling as Part of Race Prep

No matter how perfectly you fuel during a race, race-day performance starts with proper pre-race fueling and carb loading. Carbohydrate intake before a race fills your glycogen stores, giving you a solid energy reserve to draw on.

Additional Resources:

• 7 Carb Loading Meals to Power Your Performance
• Ask The Expert: Should You be Running on a Low-Carb Diet?
• Carb Loading Guide for Endurance Athletes
• The Best Gluten-Free Carbs for Athletes

When it comes to fueling, there’s no one-size-fits-all. Each athlete has unique needs and preferences, and experimenting to find what works best for you is key. If you’d rather not navigate this alone, consider reaching out for personalized guidance. My 1:1 nutrition coaching program has helped countless athletes fuel smarter and perform better.

Key Takeaways: Fueling Smarter for Endurance Performance

• Carbs are essential for endurance athletes to maintain energy and optimize performance.
• Fueling needs vary based on exercise duration: 30-75 minutes requires minimal intake, while 150+ minutes may need up to 90 grams per hour or more.
• Combining glucose and fructose in your fueling strategy enhances carb absorption and reduces GI issues.
• To prevent GI distress, gradually increase carb intake and consider flavor rotation to combat fatigue.
• Fueling is personal, so experiment to find what works best for your body and needs.

I hope this guide provides clarity and inspires you to fuel confidently during your training and races. You’ve got this! Keep fueling smart, and if you need help, check out ALN’s 1:1 nutrition coaching program for personalized guidance.