We all know football players who partake in pasta dinners the night before their football game.  This isn’t just tradition, it comes from the strategy of carbohydrate loading. It is more commonly used with runners and or cyclists as a way to improve endurance. 

When you consume carbohydrates, the body either uses them immediately for energy or stores them in the form of glycogen for later use. When blood glucose levels decline (such as during prolonged exercise or periods without food intake) the body can draw on glycogen reserves (from the liver and muscles) to provide stable energy during the sport. In other words, the body is taking the stored sugar, breaking it down and using it as energy for the endurance event, especially those lasting longer than 90 minutes [1,2].  

For this reason, many endurance athletes rely on carbohydrate loading. This typically involves consuming a high-carbohydrate diet for 1 to 3 days prior to competition, combined with a tapering of training intensity [1].  This protocol allows the muscles to store significantly more glycogen than usual, creating a larger energy reserve to delay fatigue during prolonged efforts [1].

However, carbohydrate loading is not suitable for all types of athletes or events. If you are involved in short-duration, high-intensity sports such as sprinting, powerlifting, or gymnastics, increased glycogen stores may offer little to no performance benefit. Moreover, elevated carbohydrate intake can cause water retention, bloating, and gastrointestinal discomfort, which can negatively impact performance [3]. For this reason, carb loading is best reserved for endurance-based sports such as long distance swimming, triathlon events, and marathon running. Additionally, athletes with medical conditions, such as diabetes, should consult a dietitian prior to implementing carb loading protocols.  

Our next blog will discuss ways to carb load effectively. 

References

1. Kerksick CM, Arent S, Schoenfeld BJ, et al. International Society of Sports Nutrition Position stand: Nutrient Timing. Journal of the International Society of Sports Nutrition. 2017;14(1).
2. Mata F, Valenzuela PL, Gimenez J, et al. Carbohydrate Availability and Physical Performance: Physiological Overview and Practical Recommendations. Nutrients. 2019;11(5):1084. doi:https://doi.org/10.3390/nu11051084
3. CIMSPA JRHC and F of WT Trustee at. Carbohydrate Loading | Benefits, Tips and Side Effects. UK. Published October 28, 2021. Accessed July 7, 2025. https://www.scienceinsport.com/sports-nutrition/carbohydrate-loading-benefits-tips-and-side-effects/