50 Cent raps about new fitness book, ‘Formula 50,’ and how he got his shredded body

Rapper 50 Cent says he grew up a 'chubby kid who loved pizza' but credits intense cardio workout and weights to his look

The dollar might be weak right now, but 50 Cent is strong.

Entertainer Curtis Jackson, better known as the rapper "50 Cent," has recreated himself as a weight room master.

His new fitness book "Formula 50: A 6-Week Workout and Nutrition Plan That Will Transform Your Life," which recently hit bookstore shelves, promises to unlock the secret to lifelong fitness using metabolic resistance training.

So what is his secret?

"My work out routine is always changing," he says." It should never stay the same for long periods of time. You have to challenge yourself and your muscles. When you are really regimented, it's the same over and over and you start to get comfortable. Switching up the style of training works your muscles differently."

Rapper 50 Cent performs onstage during Screamfest '07 at Madison Square Garden.

Jackson is also very conscious about what he eats and insists that the dietary aspect of the book is just as important as the workout routine.

"The dieting portion of the book is usually what people don't focus on a lot but that's what makes dramatic changes in you physically," he says. "Eating well was something I learned as I started to be successful and had to travel and perform concerts, which are an intense cardio workout."

50 Cent wasn't always muscle-bound. Growing up in Jamaica, Queens, he was a self-described "chubby kid who loved pizza."

Then, in 2000, 50 Cent was shot nine times outside his grandmother's house. Amazingly, he survived.

"And when I came back, I did a lot of physical rehabilitation because I was hurt pretty bad," 50 Cent says. "And from there, I just stayed in the gym. I was doing it at a slower pace, but that's when I started working out and I never really stopped."

For his role in the 2011 movie "All Things Fall Apart," about a college football player battling cancer, 50 Cent took his gym routine to a whole new routine in order to lose 54 lbs. in nine weeks.

"A big mistake people make when they are trying to lose weight is that they stop eating," says 50 Cent. "They'll eat salads once a day and then their body starts trying to protect itself and holds onto the fat. I was doing cardio to suppress my appetite. I felt exhausted all the time because of my weight."

After shedding so much weight, 50 Cent was then able to resculpt his body.

"I didn't just eat everything I wanted to," he says. "I put the weight back on in the right way. That was a process. Not only do your muscles have memories, but you remember where you were in the weight room. You remember where you used to be and that motivates you. It took me almost two months to get back to my regular weight. "

50 Cent's new album, "Street King Immortal," will be released in February and the rapper attributes much of his new music to his excellent mental and physical state.

"I got a little heavy during my second album," he says. "If you look at the artwork on the album, I had my shirt off and I had to draw the lines on my picture so I could have the muscles I had on my first album. But for this album I'm in good shape and I feel good."