Diet plays an important role in improving athletic performance. Our diet comprises mainly of carbohydrates, proteins and fats along with vitamins and minerals. Carbohydrates are the main source of energy for muscular activities and a sport person needs alot of energy to perform well. Thats why he needs to take more carbohydrates and less of proteins and fats. Fats are difficult to digest and delay gasrtic emptying even though they are concentrated sources of energy, yet they are restricted in the diet before athletic performance due to above mentioned reasons. Proteins are important for muscle building but before any athletic performance, a high protein diet can affect adversely as protein rich foods are broken down to urea for elimination from the body which requires alot of fluid intake as it increases chances of dehydration which will affect the performance of an athlete negatively. So proteins must be included in moderation owing to the fact that they are required for muscle formation but too much protein has to be avoided as it increases the risk of dehydration in an athlete which will exhaust him leading to poor performance. Hence, for improved athletic performance an athlete must be well-hydrated before the event. Carbohydrate loading is imperative to enhance the performance of an athlete. A high carbohydrate diet is given to athletes before performance to store as much glycogen in liver and muscles as possible so that a regular and continuous supply of energy from glucose is maintained throughout the athletic event. This helps in keeping up the energy levels of the athlete to attain peak performance without getting exhausted during an event. Hence, a high carbohydrate, moderate protein and low fat and low fibre diet along with plenty of fluids is given to an athlete before an athletic event to maximise performance. Hope this will give you a rough idea about what kind of diet is given to a sports person and why.