You know, I don't think this will really be a huge issue. There's not a lot of Muslim world class track athletes. Among distance runners it will probably only affect some of the Ethiopian runners. According to Wikipedia about a third of Ethiopians are Muslim.
The Moroccans and Algerians are also affected. Hicham el Guerrouj is a classic example of a Muslim athlete keeping faithful and patient, even after two great disappointments, before winning twice in Athens. The 1500m and 5000m finals were at night, so I doubt, had Ramadan occurred in the summer of '04, that he would not have fasted.