The 43-year-old actress has shed 36 kg but she insisted she hasn't stopped eating her favourite foods. Rebel just tucks into smaller portions because she believes people don't need to consume as much as they think, reports femalefirst.co.uk.

She told MailOnline: "I was just actually in a programme where I learned about food and they taught us that you don't really need as many calories as you think.

"Everyone thinks that you need to eat so much (and) your body needs it but the truth is your body doesn't need a lot of calories and I know it might sound crazy to some people but if you eat right and you eat small portions you'll be just fine.

"I learned that you really only need about 600 calories a day you don't need 1,500 or 2,000," the actress said.

"The problem is that people are stuck at a desk or in their car and they tend to get hungry and they want to eat because that's how they deal with stress or it's a habit but the truth is you just don't need all that food.

"A lot of people think that I don't eat carbs but I do eat carbs I just eat them in small portions. I do eat pizza and I do eat pasta I just don't eat a lot of it."

But the 'Pitch Perfect' star struggles with emotional eating.

"That is my thing. Sometimes it's hard for me because I'm an emotional eater that is my issue I eat when my emotions run high. I still struggle with that and I still work with that all the time it's just a process, it's a journey..." she said.

"My cheat food is ice cream - I really do love ice cream, and my favourite is Ben + Jerry's, it always has been, it's great quality and it's so satisfying. When I wasn't watching my weight I would sit down and eat a pint of Ben + Jerry's sometimes, it's just what I did- it was a habit - but now I'm much more careful I will have like a third of a pint and I'll eat it slowly I won't eat the whole pint at all that's in my past."

In November, Rebel welcomed daughter Royce via surrogate and she admitted the lifestyle changes of having a new baby in the house have meant both she and fiancee Ramona Agruma have gained weight.