Why You Need Carbs During a Workout: Glucose and Fructose

Carbohydrates are the primary fuel source for endurance exercise. They are stored in the muscles and liver as glycogen and are broken down into glucose during exercise to provide energy. There are two types of carbohydrates: simple and complex. Simple carbohydrates, such as table sugar, are quickly digested and provide a quick burst of energy. Complex carbohydrates, such as whole grains, take longer to digest and provide sustained energy. 

Carbohydrates and Their Roles

Having enough carbohydrates is crucial for athletes to perform well during long periods of moderate to high-intensity exercise and to recover quickly after exercise. Glucose, a monosaccharide, is the main type of carbohydrate that athletes consume during and after exercise, but the body's ability to absorb glucose can be limited by the intestinal glucose transport system. This glucose transport system, called SGLT1, is limited in its ability to shuttle large quantities of glucose that are needed during exercise. Fructose, on the other hand, is absorbed differently and can increase the number of carbohydrates available for the body to use during exercise. Fructose uses a transport system, commonly referred to as GLUT5. By ingesting exogenous glucose and fructose, athletes maximize the delivery of fuel to their muscles, increasing their ability to perform longer-duration workouts.

Two Sugars, One Goal

Combining glucose and fructose can improve endurance performance and speed up glycogen repletion after exercise. It is noteworthy that consuming too much fructose can lead to gastrointestinal distress, so it is important to find the right balance between glucose and fructose intake during exercise. Endurance athletes should aim to consume 30-60 grams of carbohydrates per hour during exercise. Speaking to a certified sports nutrition coach about your specific carbohydrate intake needs can improve your performance and recovery. 

Checkout “BREAKING DOWN THE SCIENCE OF HIGH FRUCTOSE CORN SYRUP: HOW IT AFFECTS YOUR BODY”

Post-workout Carbs

Exogenous carbohydrates play an important role in muscle repair and recovery. They help to stimulate Muscle Protein Synthesis (MPS), which is the process by which cells use amino acids to build new proteins. This is essential for repairing damaged muscle tissue and for building new muscle. In addition, exogenous carbohydrates provide the body with energy, which is necessary for MPS to take place. Without adequate energy, the body cannot repair itself efficiently and will begin to break down internal stores of amino acids and fats. Ensuring you are properly fueled for your workouts can improve sleep, and recovery, and provide greater resistance to injury. 

Conclusion

Fueling your workouts is just as important as performing the exercises correctly. Not eating the right foods before and after your workout can lead to a decrease in results, an increased risk of injury, or even illness. Eating the right foods can help you maximize your performance, reduce fatigue, and aid in recovery. Additionally, it is vital to stay hydrated throughout your workout. If you have doubts about your current fueling regimen, talk with a certified sports nutrition coach today!