How Much Carbohydrate Do I Need Per Hour During a 3-Hour Bike Race?
How Much Carbohydrate Do I Need Per Hour During a 3-Hour Bike Race?
You can have the best bike, the perfect training plan, and the strongest mindset-but if you don’t fuel right, your performance will fall short. Carbohydrates are the body’s preferred energy source during endurance events, yet most athletes either don’t eat enough or mistime their intake. The result? Fatigue, cramping, and that sudden drop in power that feels like you’ve hit a wall.
As a sports nutritionist and functional dietitian, I’ve seen athletes transform their performance simply by fine-tuning their fueling strategy. If you’re preparing for a 3-hour race, here’s how to get it right.
Why Carbohydrates Matter
During intense exercise, your muscles rely heavily on stored glycogen and blood glucose for energy. The body can only store so much glycogen-about 1,500-2,000 calories’ worth-and at moderate to high intensity, that fuel can run out in less than two hours. Once glycogen is depleted, your power output drops and your perceived effort skyrockets.
The goal during a race is to preserve glycogen by steadily supplying your muscles with external carbohydrate. This keeps your energy stable, delays fatigue, and helps you maintain pace right through the finish line.
How Much You Need
The right amount of carbohydrate depends on the duration and intensity of your race.
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Up to 60 minutes: Most athletes can rely on stored glycogen. Water or an electrolyte drink is usually enough.
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1-2 hours: Aim for 50-80 grams of carbohydrate per hour.
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2.5-3 hours (and beyond): Research shows performance improves when athletes consume 60–90 grams of carbohydrate per hour.
That’s roughly one to one and a half energy gels, or 16-24 ounces of sports drink, per hour—depending on the brand and formulation. For longer events or higher intensities, a combination of glucose and fructose (often labeled as “multi-source” or “dual-carb”) can improve absorption and reduce GI distress.
Translating the Science into Practice
Fueling on the bike takes planning and practice. Here’s how to structure your approach:
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Start early. Don’t wait until you’re tired. Begin fueling within the first 20-30 minutes of the race.
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Eat small, steady amounts. Instead of a full gel or bar all at once, aim for 20-25 grams of carbohydrate every 20 minutes. This helps maintain blood glucose and avoids stomach overload.
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Train your gut. Your GI tract can be conditioned just like your muscles. Practice your race fueling plan on long rides, starting at 45-60 grams per hour and gradually working up to 90 grams if tolerated.
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Stay hydrated. Carbohydrate absorption depends on adequate fluid intake. Most athletes should aim for 16-24 ounces of fluid per hour, adjusted for sweat rate and temperature.
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Use real food when it fits. While gels and chews are convenient, some athletes do well with small bites of banana, rice cakes, or energy waffles. Just keep the carb content consistent and easy to digest.
Common Mistakes to Avoid
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Starting too late: Waiting until fatigue sets in makes it hard to catch up.
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Too much fiber or fat: These slow digestion and can cause stomach upset during hard efforts.
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Overreliance on one product: Variety can improve tolerance, especially during long races.
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Ignoring sodium: Electrolytes support fluid balance and muscle function. Choose products that provide at least 200-400 mg sodium per hour. Testing your sweat rate will give you a more individualized approach. Click here to learn more about your fluid and electrolyte needs.
Fine-Tuning Your Plan
No two athletes are the same. Your optimal carbohydrate target depends on your body weight, training status, intensity, and gut tolerance. That’s why elite athletes don’t just grab whatever is on the course—they customize every detail.
If you’ve been struggling with energy dips or GI issues, it might be time to personalize your plan.
Book an Introductory Session to develop a fueling strategy tailored to your race demands, training schedule, and metabolic profile. Small adjustments can make a measurable difference in both performance and recovery.
Beyond the Race: Building Your Foundation
Your in-race fueling strategy only works if your day-to-day nutrition supports it. The more efficiently your body stores and utilizes glycogen, the longer you can perform at a high level. That means meeting daily carbohydrate needs, timing meals around workouts, and optimizing your recovery nutrition.
For a deeper dive into daily fueling, glycogen loading, and pre-race preparation, read my article Eating for Endurance. It outlines the principles that help athletes stay energized, lean, and ready to perform.
The Bottom Line
For a 3-hour race, aim for 60–90 grams of carbohydrate per hour, split into steady, manageable doses. Use a mix of fluids, gels, and solid options that your stomach tolerates well, and train with your plan well before race day. Combine that with smart hydration and daily fueling habits, and you’ll have the energy and stamina to finish strong.
Your fueling plan is as important as your training plan. Nail both-and your next race could be your best yet!