The wannabe-rapper, who was recently rumoured to be expecting a child with girlfriend Victoria Prince, said that his divorce from Britney Spears in 2006 triggered depression and overeating.
Federline told People magazine: "Once you get depressed, you don't really feel like doing anything. You're kind of discouraged about yourself and then the weight gain too, or that makes me more depressed... I mean, it's a combination of all of those things."
"Everybody knows what happened with me and Brit. I'm not going to say that's the total cause of it but, I mean, just not being happy with myself was probably the main part of my depression."
Federline has now slimmed down thanks to his appearance on Celebrity Fit Club: Boot Camp.