An optimal diet based on nutritional science is an essential element for athletes to achieve high performance. However, this does not apply solely to top athletes. Today, amid growing health consciousness and awareness of the importance of physical exercise, the number of people engaging in sport is rising across a wide range of age groups. They enjoy a diverse array of sports in a variety of ways. But at the same time, a sound understanding of diet is required. This article highlights the key points regarding nutritional intake for each of three categories of sporting disciplines: endurance sports, explosive power/strength sports, and mixed sports (ball sports).