Brazilian striker Ronaldo said on Tuesday that he was eight kilos overweight but hoped to shed most of the excess within a month.
"I am 1.84 metres tall and today weigh 95 kilos," the AC Milan striker said during a Brazilian television programme aimed mainly at housewives.
"In the 2002 World Cup, I weighed 87 kilos and that is what I'm trying to get back to. That's the weight I need to reach if I'm going to get back to my best."
Ronaldo ruptured a tendon in his left knee during a Serie A game against Livorno in February and is expected to need at least another seven months to recover.
The injury was similar to two injuries to his right knee earlier in his career.
"I had to stay in bed for a month," he said. "I am starting to use an exercise bike, I'm swimming a lot and using up more calories than I'm taking in."
"...I think I will be close to the ideal weight in a month."
He added: "I'm not a physiotherapist but I know what I have to do.
"My first recovery took one and a half years. I feel this time it will take much less and I think I will be back in half the time."
Last month, the three-times former world player of the year was involved in an incident with three prostitutes in Rio de Janeiro.
Police said he went to a motel in Rio de Janeiro's upmarket Barra da Tijuca neighbourhood with three call girls only to find out they were transvestites.
Ronaldo later said he was ashamed about the incident, which he described as a stupid mistake.
