The diet of a gymnast:
Most gymnasts try to get between 60 percent and 70 percent of their calories from proteins (like meats and cheeses), the rest from carbs (like whole-grain pasta, fruits, vegetables) and fats (like oils from peanuts). Because gymnastics, unlike swimming or long-distance running, is considered an “anaerobic” sport, one in which short, intense bursts of power are much more important than endurance.

Swimmer, Michael Phelps, diet:
Michael Phelps consumes 12,000 calories each day, rather than the 2,000 calorie diet of an average man. His breakfast typically consists of three fried egg sandwiches topped with cheese, lettuce, tomatoes, fried onions and mayonnaise; toast, an omelette, porridge, three pancakes and two cups of coffee. This is not all eaten at once though, before practice, he eats cereal or oatmeal, and then after practice, it’s the eggs, omelettes and veges. His lunch usually consists of 500g of pasta, with two ham and cheese sandwiches and approx. 1000 kcal of energy drinks

For dinner, he has more pasta, another 500g of it, with a pizza and more energy drinks. In addition to this he will take protein supplements to keep is muscles in top condition.

Others.

Teen athletes have unique nutrition needs. Because athletes work out more than their less-active peers, they generally need extra calories to fuel both their sports performance and their growth. Depending on how active they are, teen athletes may need anywhere from 2,000 to 5,000 total calories per day to meet their energy needs.