Female celebrities normally watch their diets closely, monitoring every morsel that passes their lips.
But Holby City's Phoebe Thomas regularly eats up to 3,000 calories a day - to fuel her passion for marathon running.
Along with her co-star Jaye Jacobs, the actress has opened up about her eating habits - with surprising results.
But while Size 8 Phoebe, who plays nurse Maria Kendall, eats five meals a day, filling up on carbohydrates like pasta and potatoes, her co-star tries to watch her weight.
Different diets: Phoebe Thomas, left, eats 3,000 calories a day to fuel her passion for running, while Jaye Jacobs loves her size 12 curves
Phoebe says that with running sessions six days a week - and double sessions twice a week - the slender actress finds it easy to stay in shape.
'My training might sound extreme, but it’s my release after filming Holby,' she told Closer magazine. 'It also means I can eat whatever I like, which is so liberating!'
Phoebe says that at 8st 4lb she is in the best shape she's ever been.
Onscreen: Phoebe as Maria Kendall and Jaye as Donna Jackson in Holby City
But the 27-year-old's diet would shock some of her fellow calorie-watching actresses.
Phoebe took up running five years ago, when she competed in a charity 5km race. She has now run five marathons, and seen big changes in her figure.
PHOEBE'S DAILY DIET
'Skipping breakfast is bad for your metabolism, so I have three pieces of toast, a banana, fruit juice, coffee and vitamins.
'Mid-morning I’ll have eight oatcakes and bananas, then lunch is a jacket potato with some protein and salad, or pasta.
'Mid-afternoon I’ll snack on a muffin or more oatcakes.
'In the evenings I’ll have steak twice a week for iron, or spaghetti bolognese or a casserole.
'We often eat at our local curry house – give me a lamb biryani and a peshwari naan bread and I’m happy!
'I don’t eat many puddings but I’ll tuck into my mum’s apple crumble.'
JAYE'S DAILY DIET
The actress loves cooking, and eats plenty of fruit and vegetables,' she revealed in Closer magazine.
'For breakfast, I have cereal with soya milk then a black coffee.
'I’ll snack on a cereal bar mid-morning and then have a home-made prawn salad or soup. I snack on Jaffa cakes or malt loaf in the afternoon.
'I’m fairly healthy by day, but at night I cook up big dinners like curries or bacon and feta cheese pie for my boyfriend.
'I also love making desserts like ice-cream with espresso coffee covered in syrup!
'I love baking and have one treat a week like a cupcake.'
'While my weight hasn’t fluctuated, my body shape has changed since I started running. I have toned arms, which I love, my hips and bum are leaner, and my legs are so toned I can barely get my skinny jeans past my calves!'
But while Phoebe loves her athletic figure, her co-star Jaye Jacobs delights in her curves.
The 27-year-old, who plays nurse Donna Jackson, says that while she'd like to lose some weight, she loves her Size 12 body.
'Some men like skinny women but I’m here for the men who like women with shape,' she said. 'I embrace my curves.
'Whether I’m a Size 8 or 14 – I’ve been both – I’ve always got hips and boobs. At the moment I’m pretty relaxed with my body.
'I have a shapely bottom and my legs are good.'
Jaye exercises regularly, and has dropped a dress size since January.
'I’ve been doing cardiovascular work as well as free weights three times a week.
I also do hatha and ashtanga yoga three times a week, which tones my arm and leg muscles and is great for my core strength – I notice if I don’t go for two weeks.'