"I was in... the nearest thing you'll get to a nightie without it being a nightie, like a long t-shirt, and bare feet," Lawson said.
The Domestic Goddess has sold more than five million copies of her cookbooks in the UK alone and is in Australia to promote her latest one, Simply Nigella.
But the 56-year-old didn't always love food, despite helping to prepare family meals from a very young age.
"My mother believed in child labour. We were like little iron chefs," she told an event in Sydney on Friday.
Lawson was brought up in a "very old-fashioned way", and if she didn't finish her food she'd be forced to sit at the dinner table alone until she she did.
"And if you still didn't, it was brought back to you cold for the next meal," she said.
The TV personality criticised the modern social media-driven clean eating movement, arguing the mantra implies a "smugness" and carries a "certain amount of food shaming".
When asked about the growing online obsession with diet, fitness and "fearing food", Lawson mentioned losing her mother, sister and husband to cancer.
"I've seen people die of cancer. I don't equate thinness with health," she said.
The bestselling author has previously spoken about her mother's eating disorder, saying she refused to be tyrannised in that way.
"But that doesn't mean that I think it's a great thing to eat 10 cream buns and take no exercise. As with everything in life, it's about balance," she said.
Lawson said avoiding processed food and opting for fresh produce was a healthier option, for those who can afford it.
"I'm always mindful that I'm in a privileged position where I can make sure I buy meat that has been humanely reared and vegetables that are organic," she said.
"But not everyone is, so I don't like to be a person who preaches."
- AAP
