The American Idol winner was recently feature in People's Most Amazing Bodies and she admitted she was worried about being pictured in a swimsuit.
She said to HollywoodLife.com: 'I have not so much as let anybody see me in a bikini except my close friends.
'So to take a picture for the whole entire world was a huge step for me.'
Sparks started to think about her health after falling ill and said she took small steps as she started working out.
She said: 'I would walk, and that turned into jogging, which turned into hiking a mountain and going to the top, which turned into Zumba classes, then 'let's see if there's a trainer'.'
She also had some advice for exercising.
Sparks said: 'If you're motivated to do it, then do it. But don't do it if you feel like you're being forced because you won't get the same results.'