How many carbs should I eat while training? A Comprehensive Guide to Fueling Your Workouts

December 4, 2025 •

4 min read

The human body typically stores enough glycogen to fuel intense exercise for approximately 90 minutes. Therefore, understanding exactly how many carbs should I eat while training is crucial for sustaining energy, especially for workouts exceeding this duration.

Quick Summary

Carbohydrate needs during training vary by exercise duration, intensity, and personal goals. Strategic pre-, during-, and post-workout fueling is essential for maximizing performance, delaying fatigue, and accelerating recovery by managing glycogen stores.

Key Points

Daily Intake Varies: Adjust your daily carbohydrate intake based on your training volume, ranging from 3-5 g/kg for light training to 8-12 g/kg for high-volume endurance athletes.
Timing is Crucial: Optimize performance by timing your carb intake; consume a complex carb meal hours before, simple carbs right before/during, and a mix of simple/complex carbs immediately post-workout.
Fuel During Long Workouts: For exercise lasting over an hour, aim for 30-60 grams of simple carbs per hour, increasing to 90+ grams for ultra-endurance efforts.
Prioritize Recovery: Consuming 1.0-1.2 g/kg of high-glycemic carbs within 30-60 minutes post-exercise, combined with protein, is essential for rapid glycogen replenishment and repair.
Experiment Individually: Use training to test your fueling strategy, find your optimal intake, and gauge gut tolerance to avoid GI distress on race day.
Not All Carbs are Equal: Choose complex carbs like oats and sweet potatoes for sustained daily energy, and simple carbs like fruit and gels for quick fuel during exercise.

The Role of Carbohydrates in Athletic Performance

Carbohydrates are the body's primary and most efficient energy source, particularly for moderate to high-intensity exercise. When consumed, they are broken down into glucose, which is then used directly for energy or stored in the muscles and liver as glycogen. This stored glycogen is the readily available fuel source that powers explosive movements and sustained efforts. As your training intensity and duration increase, so does your reliance on carbohydrate stores. Depleted glycogen can lead to muscle fatigue, reduced performance, and a higher perceived effort. Properly managing your carbohydrate intake is therefore fundamental to any serious training regimen.

Different Carb Types: Simple vs. Complex

Not all carbohydrates are created equal, and understanding the difference is key to timing your nutrition effectively.

Complex Carbohydrates (Lower Glycemic Index):

Digested slowly, providing a sustained, steady release of energy.
Rich in fiber, vitamins, and minerals.
Ideal for daily meals and fueling several hours before a long workout.
Examples: Whole grains (oats, brown rice, quinoa), sweet potatoes, legumes, and whole-wheat pasta.

Simple Carbohydrates (Higher Glycemic Index):

Digested and absorbed quickly, offering a fast-acting energy boost.
Best for immediately before, during, or right after a workout when rapid energy is needed.
Examples: Fruits (bananas, raisins), sports drinks, energy gels, and white rice.

How to Time Your Carbohydrate Intake

Strategic timing is just as important as the quantity of your carbohydrate intake. Your needs change depending on whether you are fueling for daily training, pre-workout, during exercise, or for recovery.

Daily Intake by Training Volume

Your total daily carbohydrate intake should be periodized based on your training load. General guidelines (per kg of body weight) include:

Light Training (<1 hour/day): 3-5 g/kg.
Moderate Training (~1 hour/day): 5-7 g/kg.
High-Intensity Training (1-3 hours/day): 6-10 g/kg.
Very High-Intensity/Endurance (>4-5 hours/day): 8-12 g/kg.

Pre-Workout Fueling

To top off liver and muscle glycogen stores before a significant session, plan your pre-workout meal 1 to 4 hours in advance.

4+ hours before: A full meal with complex carbs, moderate protein, and low fat/fiber is ideal. (e.g., oats with berries, grilled chicken with brown rice).
1-2 hours before: A smaller, easily digestible snack with moderate carbs. (e.g., a banana with nut butter, toast).
< 60 minutes before: A small amount of easily digestible simple carbs to prevent blood sugar drops. (e.g., a sports drink, energy gel, or a few crackers).

Fueling During Your Workout

For workouts lasting over 60 minutes, consuming carbohydrates during exercise helps maintain blood glucose levels and delay fatigue. The optimal amount depends on duration and intensity.


Exercise Duration	Recommended Hourly Carb Intake	Example Source	Notes
30-75 minutes (High-Intensity)	Mouth Rinse or <30g	Sports drink rinse	Signals the brain for an energy boost without heavy digestion.
1-2 hours (Moderate-to-High)	30-60 grams	Gels, chews, or sports drinks (6-8%).	A mix of glucose and fructose may aid absorption.
2-3 hours (Endurance)	60-90 grams	Gels, chews, diluted juice, bars.	Gradually increase intake to train your gut.
3+ hours (Ultra-Endurance)	90-120+ grams	Multi-carb sources (e.g., gels with glucose-fructose mixes).	Elite athletes can train their gut to tolerate higher amounts.

Post-Workout Recovery

The 30-60 minute window immediately following exercise is critical for glycogen replenishment. Your goal should be to consume 1.0-1.2 grams of high glycemic index carbohydrates per kilogram of body weight, especially if another session is planned within 24 hours. Combining carbs with protein (in a 3:1 or 4:1 ratio) can further enhance glycogen synthesis and promote muscle repair.

The Great Debate: High-Carb vs. Low-Carb Training

While a high-carbohydrate approach is widely accepted for maximizing high-intensity performance, some athletes explore low-carb or ketogenic diets.

High-Carb Advantages: Maximizes glycogen stores, directly fueling high-intensity efforts, and supports hormonal balance for muscle growth.
Low-Carb Advantages: Promotes fat adaptation, training the body to use fat more efficiently, which can benefit very long, lower-intensity endurance efforts. Can be useful for fat loss goals but may hinder high-intensity output.
Carb Periodization: An advanced strategy where athletes strategically manipulate carbohydrate intake based on training demands. High-intensity sessions are fueled by high carbs, while lower-intensity days or fasted training periods enhance fat oxidation and metabolic flexibility. This approach may offer the best of both worlds, though it requires careful planning.

For most athletes and those training for general fitness, a moderate-to-high carb approach, periodized around training, is the most effective and sustainable strategy. For those considering low-carb, be aware of the potential for reduced high-intensity performance and the long adaptation period. For further research on athletic nutrition strategies, consult scientific resources like the Gatorade Sports Science Institute.

Practical Tips for Fueling Your Training

Experiment with your timing: Don't wait for race day to test your fueling strategy. Practice during training to find what your body tolerates best and avoid gastrointestinal issues.
Choose real foods: While gels and drinks are convenient, whole food sources like bananas, rice cakes, and dried fruit are excellent options for fuel during training.
Listen to your body: Pay attention to how you feel. If you're experiencing energy crashes or fatigue, you may need to adjust your intake. Factors like stress and sleep also play a role in energy levels.
Stay hydrated: Carbohydrate intake is closely linked to hydration. Many sports drinks provide both carbs and electrolytes, which is crucial for longer efforts.

Conclusion

Determining the right amount of carbohydrates to consume while training is not a one-size-fits-all answer but depends on the duration and intensity of your exercise. For daily training, align your intake (typically 3-10+ g/kg) with your training volume. Strategic timing is key, with complex carbs supporting daily energy and simple carbs reserved for immediate pre-, during-, and post-workout fuel. By periodizing your carbohydrate intake and carefully listening to your body's response, you can optimize your performance, accelerate recovery, and achieve your fitness goals more effectively.

Frequently Asked Questions

For moderate training, typically around one hour per day, a daily carbohydrate intake of 5-7 grams per kilogram of body weight is recommended.

A low-carb diet can enhance fat adaptation for long, lower-intensity endurance events but may hinder performance during high-intensity exercise, which relies on glycogen for fuel. For most high-performance goals, a high-carb diet is more effective.

If you have less than an hour before your workout, consume a small amount (around 30g) of simple, easily digestible carbohydrates like a sports drink, an energy gel, or a piece of fruit like a banana.

For endurance events over 2.5 hours, aim for 60-90 grams of carbohydrates per hour. You can multiply this hourly target by the total expected race duration to estimate your total needs.

After exercise, particularly high-intensity or long-duration sessions, your muscle glycogen stores are depleted. Consuming carbohydrates within the recovery window (30-60 minutes) helps to rapidly replenish these stores, preparing your muscles for the next training session.

For muscle building, a balance of complex and simple carbohydrates is beneficial. Complex carbs like sweet potatoes and brown rice provide sustained energy for workouts, while simple carbs post-workout quickly replenish glycogen and promote muscle repair.

Carb loading involves increasing your carbohydrate intake and decreasing training intensity in the 36-48 hours leading up to a long endurance event to maximize muscle glycogen stores. It is most effective for events lasting over 90 minutes.