Your statement strikes me as patently false. Athletes eat a ton of food while training. Michael Phelps, for example, eats over 10,000 calories per day.
The point was not that Phelps is a representation of all athletes, but rather that athletes do eat a ton of calories a day in order to build muscle mass and have enough stamina for their rigorous training. There are certain exceptions, but generally speaking, if you are training for a sport then you should have a solid diet.