The singer, who shot to fame on X Factor in 2012, told host Christine Lampard that she’s slimmed down by cutting out the “three B’s” – beer, biscuits and bread.
Lucy, 28, said she had to “knock these on the head” as she thought she looked “awful”.
She told Christine: “The three B’s… I had to knock them on the head.
“I had been in a bad place for a long time, I’ve been very open about that.
“I looked at pictures before and physically I was in a bad place.”
Lucy even admitted to Christine that she was “surprised” no one had told her that she “looked awful”.
The songstress, who is known for hits such as Tea & Toast and You’re Too Young also spoke about touring and playing Glastonbury twice.
She revealed she’s been touring since last September and is set to be back doing more shows soon after releasing her latest album Today Was a Good Day back in May.
The star told Christine: “I’ve enjoyed being back on the road yeah.
“I’ve been touring since September, so nearly a year.”
Talking about Glastonbury, she added: “I’ve done it twice, I’m the only X Factor contestant to have played Glastonbury.
“It’s an honour to be asked to do it.”
Lorraine airs weekdays on ITV at 8:30am.