This paper presents the interrelationship of diet and the effects of diet on sports performance and presents all the elements that determine it. Nutrition is crucial in today's life of athletes and without proper nutrition it would not be possible to reach maximum possibilities. With the advancement and development of sports, the intensity and difficulty of training increase and higher goals are set. This paper presents all nutrients and how and to what extent they should be consumed. Examples of sports nutrition, menus and nutritional tables showing the amount of individual nutrients in foods that would be desirable to consume are presented. Due to increasingly difficult training and greater effort, athletes are advised to take certain dietary supplements to more easily withstand the effort and speed up recovery. There are also some alternative diets in sports such as vegetarian diet and gluten free diet which have also proven to be successful to some extent.