But the US X Factor judge says she is no longer a slave to the scales and swears that she now eats whatever she wants.
'It's taken a long time to get here,' the 33-year-old former Pussycat Dolls star tells Shape magazine.
'I started jogging and counting calories when I was just 14. I've been on every diet you can imagine.
'By the time I was in the Pussycat Dolls, I was on the [scales] all the time. It became my enemy because I noticed that when I exercised really hard, I'd gain weight.
'Now that I'm in my 30s, I've stepped off the [scales]