PARIS (AFP) - Jamaican track star Usain Bolt has admitted to sacrificing fast food in a bid to extend his stellar sprinting career.

In an interview with the IAAF Inside Athletics programme released on Tuesday, Bolt said curbing off-track activities as the years rolled by had been easy compared to having to watch his diet.

"I've cut back on a lot of things," said the 28-year-old six-time Olympic gold medallist who had a growing reputation in his younger years for liking the nightlife and, famously, eating chicken nuggets.

"When I really realised I was getting older was last season when I got injured.

"Trying to get back was much harder than the years when I was younger. Now it takes time for me to get going and I need a lot more races.

"I've noticed that I have to be very careful and I just have to be aware of everything around me and make sure I'm on point.

"I've started eating healthy. That's the hardest thing for me right now is the sacrifices, eating vegetables all the time.

"Everything else is easy to give up, but eating healthy is really hard."

Bolt, who has been struggling with a pelvic injury but is slated to compete at the Diamond League meet in London on Friday, made no mention in the programme about next month's World Championships in Beijing.