Fuel the Fire: Leading up to your race, make sure to eat nutrient-dense foods to ensure good fuel storage and recovery at the muscular level both during your training and during the actual race. The body will only work as hard as you will allow it; therefore, good nutrient sources of carbohydrates, fats, and proteins are the key to better performance. One of the more talked about diet techniques leading up to races is the carbohydrate loading that can begin up to 7 days prior to the competition. If done correctly, the carbohydrate loading technique can be a useful tool for optimal performance.
Read this article to get a better understanding how carb loading works and how to apply it: CarbLoading