Renee's pizza diet

The extra pounds required to become the plump, Bridget Jones were one of the reasons why Renee Zellweger was reluctant to reprise her Oscar-nominated role. But after accepting the part, she is now consuming more than 4,000 calories a day - double the recommended number for a woman.

Miss Zellweger now starts her day with a Big Mac and large fries, savoury scones with gravy and a multi-fat milkshake.

Throughout the day she eats 20 sugary doughnuts, peanut butter and pizza before having a giant portion of spaghetti with meat sauce and potatoes saturated in butter for dinner.

She is consuming more than 4,000 calories a day - double the recommended number for a woman.

Miss Zellweger said: 'It's easier for me this time round because I know what I have to do and how to do it.

'I have to stick to it because I found out last time that one doughnut doesn't do a thing. You've got to eat 20 a day for five weeks before you get results.'

She said that, although reluctant to gain more weight, it was essential if she was to play the part properly.

Miss Zellweger told Closer magazine: ' It would be silly if Bridget was talking about her chubby thighs and they weren't chubby.'

Three years ago she gained 20lb in 12 weeks to star in Bridget Jones's Diary. Reports suggested she found it hard to lose the extra pounds once filming had finished.

A source close to the actress said: 'Although the idea of eating so many calories isn't that appealing to her, she knows it's what she has to do. So she's eating anything and everything and has largely stopped exercising so she can gain all that weight over again.'

Last night nutritionist Roz Kadir, who has worked with the England rugby squad and Everton football club, warned that the actress could face health problems.

'By suddenly eating a lot of sugary foods she is running the risk of developing Type 2 diabetes as her pancreas will really be pushed to process all that sugar,' she said.

'Her digestive system may also be affected - her liver will have to work overtime - and she will suffer from bloating.

'Renee's skin will also stretch a lot and may lose some of its elasticity when she shrinks back to her original size.

'When you lose a lot of weight quickly you also run the risk of losing muscle as well as fat, which is never good.'