By Karyn Guidry, founder of Karyn Guidry Fitness
When it comes to hybrid racing, nutrition can make or break your performance. HYROX demands both endurance and strength, fast 1K runs paired with taxing functional stations. To perform your best, carbohydrates play a leading role. The question is: should you rely on carb loading before race day or focus on consistent daily carb intake during training? Let’s break it down.
Carbohydrates are your body’s preferred fuel source for high-intensity exercise. Your muscles store carbs as glycogen, which becomes the energy you rely on when sprinting between stations, pushing the sled, or finishing those final wall balls.
When glycogen runs low, performance drops. Fatigue sets in, pace slows, and every movement feels heavier than it should. Managing your carb intake properly ensures your tank is full when it matters most, both in training and on race day.
Carb loading is the practice of temporarily increasing carbohydrate intake (typically 2–3 days before an event) to maximize glycogen stores. The goal is to “top off” your energy reserves so you have more available fuel when it’s time to compete.
When it works best: Long events lasting over 90 minutes, where glycogen depletion becomes a limiting factor.
How it looks: Increasing carbohydrate intake to around 8–10g per kilogram of body weight per day, focusing on easy-to-digest options like rice, pasta, oatmeal, and bread.
Risks: Overdoing it can cause bloating, sluggishness, or digestive discomfort if your body isn’t used to it.
For HYROX athletes, who typically race between 60–120 minutes depending on category and fitness level, carb loading can be helpful, but only when built on a foundation of consistent daily fueling.
Carb loading might grab attention, but your daily carb habits during training are where true performance gains happen. Consistent fueling ensures your body is ready for every workout, supports recovery, and helps you adapt to training demands.
Training days: Moderate to high carb intake (4–7g per kilogram of body weight) helps restore glycogen after runs, lifts, or HYROX simulations.
Recovery days: Slightly lower intake (3–5g per kilogram) works well since energy demand is reduced.
Think of glycogen like a bank account, you can’t withdraw what you haven’t deposited. If you’re chronically under-fueled, carb loading won’t fix it. Regular daily deposits are what build your reserves.
It’s not about choosing one or the other. The best strategy combines both.
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Prioritize steady daily carb intake during training to maintain performance and recovery.
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Adjust carbs to match your training intensity (higher on interval or race-sim days, lower on easy days).
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Add a carb loading phase in the final 48 hours before race day to fully stock glycogen stores, especially if your race is expected to last longer than 75 minutes.
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Stick to familiar, low-fiber foods to avoid stomach issues, race week isn’t the time to experiment.
Practical Example
Let’s look at a 70kg (154lbs) HYROX athlete:
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Daily training fueling (moderate day): |
Carb loading (race week, final 2 days): |
| 350–420g carbohydrates (5–6g/kg), spread evenly across meals and snacks. | 560–700g carbohydrates (8–10g/kg), focusing on simpler carbs and tapering fiber intake. |
Key Takeaways
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Carb loading is a short-term strategy best used before race day.
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Daily carb intake is what supports long-term training, energy, and recovery.
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The best HYROX athletes fuel consistently throughout training and then top off glycogen before competition.
Bottom line: You can’t out-carb-load a poor daily fueling strategy. Build your nutrition foundation first, then use carb loading as the final edge that helps you perform at your best when it counts.