Complex sentence: It is concerned with the type and quantity of fluid and food taken by an athlete, and deals with nutrients such as vitamins, minerals, supplements and organic substances such as carbohydrates, proteins and fats.
Split into simpler sentences: It is concerned with the type, as well as the quantity of fluid and food taken by an athlete. In addition, it deals with the consumption of nutrients such as vitamins, minerals, supplements, which also include organic substances such as carbohydrates, proteins and fats.