The pop star admitted that she may have done herself "permanent damage", due to her efforts to control her size during her rise to fame.
After the reformation of the girl-power pop group last week, Sporty Spice claimed she wanted to be a better role model for young fans second time around.
She told The Sun: "I was underweight and my image was unhealthy. There were kids who were looking up to me. I want to rectify any of the damage I caused.
"I got so thin my period stopped and my bones became very fragile. I may have done permanent damage."
She added: "I went to the gym and trained constantly. I wasn't eating properly. I wanted to get as perfect as I could, knowing perfection is impossible, and that got me very sick."