Each athlete has a unique constitution; so there is no single diet that can meet the requirements of all athletes at all times. Good food choices and a strictly-followed diet will support the intensive trainings you require while limiting the risk of injuries.
So, irrespective of whether you are a man or a woman, your age, or your level of competition, a good diet will help you:
Achieve and maintain an ideal body weight
Support your training programs
Limit your risks of injury and illness
Help to recover quickly from injury and illness
Enhance your performance consistently
Despite the benefits, there are challenges that athletes face to meet their dietary goals. Most common ones are:
Not having the resources to afford the advice of dietitians
Unavailability of registered sports dietitians in the area
Non-availability of good food choices
Limited or no knowledge of diets
Lack of time in following the diet strictly and consistently because of frequent traveling or busy lifestyle
Ultimately, exploring food choices, including high fiber, low glycemic foods at every meal, and making the most of seasonal fruits and vegetables, could limit these challenges.

FROM: http://www.medindia.net/patients/lifestyleandwellness/diet-and-nutrition-tips-for-athletes.htm