The Big Brother's Little Brother host, who had daughter Isabelle in June last year, said that she no longer worries about problems to do with work or her weight since giving birth.
Willis, who is hosting this year's Britain's Next Top Model Live event, told DS: "That job you worried about getting, the shoes that you wanted, that bit of fat on your arse, it goes out of the window when you have a baby,
"You just think, 'It's all about my baby from now'. You just think, 'F**k this man, nothing is that important'."
When asked about the controversy surrounding plus size models on Britain's Next Top Model, Willis said: "It's an individual thing and you've got to hope that these girls are grounded enough and sensible enough not to take things too far. That's what they should be told. Not to lose a few more pounds, we need to see more bone. It's a tricky subject."
Speaking about her experiences as a model when she was younger, she added: "I was told once that I needed to lose a few pounds and I cried for a little while going, 'Oh God, what's wrong with me?' but then I went, 'Do you know what? I just don't care'.
"I like cake. And I like wine. And I'm not going to stop eating and drinking it to be paid a few hundred quid and walk down a runway. It doesn't mean that much to me. I would rather feel good about myself and have a chocolate bar."
Britain's Next Top Model Live takes place at London's ExCeL centre from October 22 to October 24.