Carbohydrates for Athletes: Fueling Performance, Recovery, and Endurance with the Right Nutrition

As an athlete, I have personally experimented with different fueling strategies and carbohydrate intake. I have discovered that the fuel source I use can make all the difference in my performance outcomes. Finding your fuel can be just as much work as the actual training you are doing, especially when you consider all the differing tolerances and intolerances. Let’s explore carbohydrates and why they are important for athletes. 

The Role of Carbohydrates in Energy Production

When consumed, your body breaks down carbohydrates into a monosaccharide, or simple sugar, also known as glucose. This is the main energy source for cells in the body, as it is fast-acting and works best as fuel when energy demands increase. Once immediate demands are met, additional glucose is stored in the form of Glycogen, which can be found in the liver and muscles. 

• Muscles: glycogen stored in muscles is used for localized energy needs, specifically during exercise or when demand is put on a particular muscle group. 

• Liver: this form of stored glycogen is used as a generalized energy source during fasting or between meals when the body needs energy. 

Two main hormones play a role in glucose storage and use. The first is insulin, which helps convert excess glucose into glycogen, a form of stored energy. When your body needs energy, the hormone glucagon helps break down glycogen into glucose and release it into the bloodstream for use. 

When considering athletic performance, having enough energy or carbohydrates available is crucial. If you haven’t replenished your glycogen stores after a hard workout or event, you'll face negative impacts, and your body won't be able to meet the next demand you put on it. Being in a constant state of stress with little to no fuel is a first-class ticket to Bonkville. (“Bonking” is a term athletes use when referring to having a terrible performance due to poor fueling, GI, or hydration strategies.)

Carbohydrate Loading: A Strategy for Endurance Athletes

For endurance athletes, it's essential to maintain a balanced diet and adequate fluid intake throughout training. Leading up to race day or the event you're training for, you can consider carbohydrate loading as a way to top off your glycogen stores. This helps ensure your muscles have been refueled and that you don't deplete glycogen as quickly.  Studies show that Carb loading really only benefits athletes who are going distances of 30 kilometers or more. So, if you're planning anything shorter, make sure to focus on a good balance of nutrients throughout all your meals and snacks.

When it comes to timing and planning your nutrition for pre-race and during the event, you must start at the beginning of your training cycle. Your nutrition plan, fueling, and hydration are just as important as the actual training you do. If you're looking for more detailed guidelines, you can check out this article: Optimizing Nutrition for Endurance Athletes. Though it was written for those who suffer from runner's colitis, it applies to all endurance athletes. As for Carb Loading, you wouldn't start doing that until about 36 hours before your main event. 

Post-Workout Carbohydrate Intake: Replenishing Energy Stores

Now that we have covered carb loading and fueling during your activity, let's discuss post-workout intake and how to optimize your nutrients and timing. After any type of activity that creates a demand on your muscles, you will have what is called an anabolic window. This is the period, usually about 30-60 minutes, when your muscles are most receptive to nutrient absorption, notably carbohydrates and protein. Recent studies have shown that this may be a sliding window, dependent on the state of training one is in, as well as whether the workout was done fasted or if a pre-workout meal was consumed. 

One common misconception is that the anabolic window should be filled with a high concentration of protein. It is more important to focus on carbohydrate intake to replenish your glycogen stores, with minimal protein intake during this period. If you are looking for a ratio, it should be 4 g of carbs to 1 g of protein, choosing options that are best tolerated, whether in liquid or solid form. If protein intake is consistent throughout the day, your muscles will receive the necessary amount for repair, increased strength, and growth. Aiming for 20-40 g of protein at each meal is an ideal goal to meet your body’s needs, depending on your workload and stress. 

Hydration and Electrolyte Balance: Essential for Optimal Performance

As I mentioned earlier, hydration is just as important as nutrition when it comes to performance and recovery. Part of getting rehydrated and staying hydrated involves incorporating electrolytes into your diet. Common electrolytes include Potassium, sodium, magnesium, calcium, chloride, and phosphate. These are essential for balancing fluid in and out of cells, muscle contraction (this includes your heart!), blood pressure, and nerve signals. Combining electrolytes with water allows you to replace what is lost through sweat, urination, and any potential GI issues. 

Carbohydrates, fluid, and electrolytes are all essential for athletes and their performance. Whether you are fueling muscles, repairing them, or replenishing nutrient losses, it is vital to understand why and how to do this. Medals, titles, and bragging rights are often lost due to poor fueling strategies. Set yourself up for success by understanding the importance and learning what works best for your body. 

1. _{Arent, S. M., Cintineo, H. P., McFadden, B. A., Chandler, A. J., & Arent, M. A. (2020). Nutrient Timing: A Garage Door of Opportunity?. Nutrients, 12(7), 1948. https://doi.org/10.3390/nu12071948} 

2. _{Glycogen: What it is & function. Cleveland Clinic. (2025a, March 19). https://my.clevelandclinic.org/health/articles/23509-glycogen} 

3. _{Hearris, M. A., Hammond, K. M., Fell, J. M., & Morton, J. P. (2018). Regulation of Muscle Glycogen Metabolism during Exercise: Implications for Endurance Performance and Training Adaptations. Nutrients, 10(3), 298. https://doi.org/10.3390/nu10030298}