His career was marked with severe injuries. Some doctors said he would never play at top level again, until he proved everybody wrong in 2002 WC.
Same thing happenning with Ronaldhino, magical player that partying hard and eating ruined their careers. Had they avioded that they could have easily had another 4 productive season's in top flight football.
Tough to say that eating and partying ruined Ronaldo, given his copious knee injuries. It certainly didn't help, but having dental floss for ACLs is a pretty major contributor.
Eating played a major part in his decline in performances, which obviosly affected his agility, pace. You look at Ronaldhino and he doesn't have any recurring injuries but ever since he started eating alot and partying his perfomances went drastically down, Barcelona had to sell him, good on them since they still managed to make a decent profit while he was still a comodity in europe.