The singer has adopted the 80/20 diet - which means she watches what she eats from Monday to Friday, but indulges herself at the weekend.
"I've learnt not to be afraid of food," Mel told the Mail. "I have my 80/20 rule where through the week I try to be healthy — and then at weekends, I'm a lot more relaxed, especially in front of (daughter) Scarlet.
"My downfall is crisps and lager, but they're usually reserved for weekends."
It is not the first time that Mel has spoken about the impact having a child has had on her diet. In the past she said that having Scarlet, now five, "saved" her.
"When I was in the band I hardly ate and I exercised obsessively as I was so focused on my weight," she admitted. "As my bump grew, the more proud I became of my body and suddenly I felt more comfortable eating healthy."
Now, Mel had cut her training sessions down from six-a-week to four, and has taken up yoga.
"I felt most of my 20s feeling self-conscious about certain parts of my body, but as I've got older I feel more feminine," she revealed.
"After having a child, it makes you realise how incredible your body is and it's made me a lot kinder to myself. Becoming a mum gave me the freedom to finally love myself physically."