Kay is an aspiring 800 m track athlete who has read various nutrition books with the hope of finding the ideal diet for her sport. From her reading, she has learned that fats yield more calories per gram than carbohydrates. In addition, she knows that dietary proteins are needed to help her muscles recover from training and additionally can be used for energy. She is now convinced that one of the popular high-fat, high protein, low carbohydrate diets is her best choice. Her coach disagrees with her decision. She recommends that Kay speak with a sport nutrition professional prior to changing her current diet, in which the majority of calories come from carbohydrates.