The 'Price Tag' hitmaker watches what she eats but said she likes a naughty treat of mashed potato, gravy and cheese while her entourage indulge in their favourite takeaways, reported Femalefirst.
"I eat a lot of fruit and a lot of veg, and I drink a lot of water, but I love my carbs. I don't really eat junk food. It's the only thing I'm not a fan of.
"But when it's, like, midnight and nowhere else is open, I'd much rather have mashed potato, gravy and cheese. That's my naughty thing, instead of just saturated, mixed-up meat in a burger," she said.
The 24-year-old singer's healthy eating regime started at a young age and she credits her mother's attempt to ban her children from eating at fast food chains.
"When I was young my mum, bless her, used to make potato wedges with little bits of chicken and put them in a little box with an 'M' on it and tell us it was from McDonalds."