How Many Carbs Should You Eat Per Hour?

October 28, 2025 •

4 min read

According to sports nutrition research, consuming carbohydrates during prolonged exercise is essential for maintaining energy levels and improving performance. The specific amount of carbs you should eat per hour, however, is not a one-size-fits-all answer, as it depends on the intensity and duration of your activity. Understanding these guidelines is crucial for endurance athletes seeking to maximize their potential and avoid the dreaded energy crash.

Quick Summary

This article explores the recommended hourly carbohydrate intake for athletes during exercise, detailing specific amounts for varying durations and intensities. It explains why fueling is essential, how the body processes different sugars, and provides practical advice on choosing the right fuel sources and training your gut for optimal absorption.

Key Points

Duration is Key: Fueling needs change significantly with exercise length. Short workouts (under 60 min) need no carbs, while longer sessions require planned intake.
60-120 Minute Efforts: Aim for 30-60 grams of carbs per hour for moderate to intense sessions, using simple, easily digestible sources like gels or sports drinks.
Endurance Efforts (>2 hrs): Increase intake to 60-90+ grams per hour, using products with multiple transportable carbohydrates (e.g., glucose and fructose mixes) to enhance absorption.
Train Your Gut: Practice your fueling strategy during training to help your digestive system adapt and avoid gastrointestinal distress on race day.
Mix Up Your Fuel: For ultra-endurance events, consider incorporating real foods along with gels and drinks to combat flavor fatigue and provide varied nutrients.
Listen to Your Body: Individual tolerance varies. Start at a conservative intake and adjust based on your performance and how you feel.

Understanding the Science of Fueling Your Body

During prolonged and intense exercise, your body primarily relies on stored glycogen (carbohydrates) for energy. As these stores deplete, performance suffers, a phenomenon athletes commonly refer to as 'bonking' or 'hitting the wall.' The strategic intake of exogenous carbohydrates (from external sources like gels, drinks, and chews) during exercise helps replenish this energy, allowing you to sustain your effort for longer periods. The amount and type of carbs you consume are critical factors in this process, influencing both your energy levels and your risk of gastrointestinal (GI) distress.

Carb Intake Recommendations by Exercise Duration

Your hourly carbohydrate needs directly correlate with the length of your workout. Longer events require higher intake to keep up with energy demands.

Exercise Lasting 1-2 Hours

For exercise sessions lasting between 60 and 120 minutes, a moderate carbohydrate intake is recommended. Experts suggest consuming 30–60 grams of simple carbohydrates per hour to maintain performance. This is suitable for most moderate to high-intensity efforts, such as a long-distance run or a cycling session. For example, a single energy gel (around 20-30g of carbs) every 30-60 minutes, or a bottle of isotonic sports drink, can help meet this requirement.

Exercise Lasting 2-3+ Hours

Once your activity extends beyond two hours, your body's energy needs increase significantly. For these prolonged endurance events, like marathons or triathlons, a higher carbohydrate intake of 60–90 grams per hour is often necessary. To achieve these higher rates of absorption without causing stomach upset, many sports nutrition products utilize a mixture of different carbohydrates, such as glucose and fructose. These different sugars use separate transport pathways in the body, allowing for a higher total absorption rate compared to glucose alone.

Ultra-Endurance Events (>6 Hours)

For ultra-endurance events, fueling becomes even more strategic. Some elite athletes train their guts to handle even higher intakes, sometimes exceeding 100 grams per hour. However, this requires careful practice and is not recommended for everyone. For these extremely long sessions, many athletes incorporate a mix of carbohydrate sources, and sometimes a small amount of protein and fat, from real foods to avoid flavor fatigue.

The Role of Glucose-Fructose Ratios

To maximize carbohydrate absorption and minimize GI issues during exercise, the ratio of glucose to fructose in your fuel source is important.

2:1 Glucose:Fructose: This has been a long-standing standard recommendation for intakes of 60–90 grams per hour, as it helps utilize two different absorption pathways.
1:1 Glucose:Fructose: Newer research suggests that a 1:1 ratio might allow for even higher absorption rates, with some athletes tolerating up to 140 grams per hour. However, this advanced fueling strategy requires specific gut training.

Comparison of Fueling Strategies by Activity Duration


Exercise Duration	Recommended Carb Intake (per hour)	Example Fuel Sources	Key Strategy
1-2 Hours	30-60 grams	Isotonic sports drink, energy gels, sports chews	Moderate intake to maintain energy; easily digestible sources.
2-3+ Hours	60-90+ grams	Multiple transportable carbohydrate drinks (glucose/fructose mix), gels, energy bars	Higher intake using dual-carb sources to increase absorption capacity.
>6 Hours (Ultra-Endurance)	90+ grams (with gut training)	High-carb drinks, gels, chews, plus small amounts of real food, fat, and protein	Maximize absorption through trained gut; incorporate real foods for variety and satiety.

Tips for Training Your Gut

Your stomach is trainable, similar to your muscles. To prevent GI distress, it is crucial to practice your fueling strategy during training, not just on race day. Start with a lower carb intake and gradually increase it over time to allow your body to adapt. Experiment with different fuel types—gels, chews, bars, and drinks—to find what works best for you. Listen to your body and pay attention to how different sources affect your digestion and energy levels.

Conclusion

Determining how many carbs you should eat per hour depends heavily on your specific exercise duration and intensity. For shorter, intense efforts (1–2 hours), 30–60 grams per hour is a solid starting point. For longer endurance events, scaling up to 60–90 grams or more, often using a mix of glucose and fructose, is essential for sustained performance. Practicing your fueling strategy during training is non-negotiable for gut comfort and optimal results. By understanding these principles and tailoring your approach to your own body's needs, you can effectively fuel your athletic performance and crush your goals.

Sources

Frequently Asked Questions

For workouts lasting one hour or less, your body's stored glycogen is usually sufficient, so eating during the workout is not necessary.

If you don't consume enough carbohydrates during prolonged exercise, your body's glycogen stores will deplete, leading to a loss of energy and a significant drop in performance, a feeling known as 'bonking'.

Effective absorption is indicated by sustained energy levels without any stomach discomfort, gas, or bloating. Consistent energy, no cramping, and overall well-being are good signs of proper fueling.

Yes, real food like bananas or raisins can provide carbohydrates during exercise. However, sports nutrition products are often formulated for rapid digestion and specific glucose-fructose ratios to maximize absorption.

Start by gradually increasing your hourly intake during training sessions, using a consistent strategy of drinks, gels, or chews. This progressive approach helps your gut adapt to processing more carbohydrates during exercise.

Historically, the maximum absorption rate was thought to be around 60 grams per hour using glucose alone. However, using a mix of glucose and fructose can increase absorption rates, with some athletes training their guts to process over 90 grams per hour.

For exercise lasting longer than 90 minutes, it's beneficial to start consuming carbohydrates early and consistently, often in small, regular doses every 15-30 minutes, to avoid a depletion of energy stores.