Story or Book would be mid-1990 or earlier as that is when I read it. Scenes I remember:

1. Boy entering the office of his father/guardian and giving the exact time to the second since he was last there. Had the ability to keep perfect time.
2. The father/guardian being summoned to the boy's school/boarding school because he refused to eat or drink. He told the school that there was something wrong with the food/drink. They insisted that the food from the food processors was perfectly fine. Turns out there were minute traces of a harmful chemical that the boy somehow detected.
3. He was a young man and applying for some program. He and the other candidates were placed in small rooms and left without further instructions. They were all being observed to see what they would do. This guy tilted back his chair, closed his eyes, and slowed his breathing/heart rate so low that he freaked the observers out. The observers barely altered the CO2/O2 levels to his room and he instantly snapped awake and righted his chair.