Nadine Baggott reveals the real world of the most glamorous celebrities. This week: how Bar Refaeli, Cat Deeley and Liv Tyler stay in perfect shape

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Following on from my recent celebrity beauty secrets that are worth knowing post, I want to share some shape up, slim down body secrets too. Again, this is not all just ‘"rink water and go for a run" dross; it’s the celebrity fitness secrets that really work. Sadly there are no miracle pills, shakes or fat=dissolving machines, but there are some insider secrets that make sense.

Miranda Kerr: Eat Low GI

"I eat low GI foods, drink filtered water and eat mostly fresh produce and very little meat. For me it’s about ensuring I get the nutrients from my food, not about counting calories. I eat extremely healthy because when I do, I have more energy."

This Victoria’s Secret model knows her stuff and she’s right: a low GI, or glycaemic index, ie, low sugar diet is currently the hottest and, many say, most effective and healthy way to lose weight.

Liv Tyler's Quick Fix Guru

"If I have a goal like a shoot or a role or something specific that I need to get in shape for then that’s often when David Kirsch helps out. He is great at getting me into really good shape. I follow his programme for a week or two and it shows really quick results. You work out every day and have a shake for breakfast and a shake for lunch and then protein and a big salad for dinner and maybe an apple or one of his bars and lots of vitamins and supplements. It really works for me."

David Kirsch products are available in the UK at Space NK.

Cat Deeley: Invest In A Personal Trainer

"I am not a gym bunny. It doesn’t work for me; I feel like a hamster on a wheel and have no interest in schlepping my way to a gym and sweating with lots of other people in a small space. I prefer hiking, being outside, I love horse riding and I love yoga. I have a great teacher who comes to my house and I fully admit it is a complete luxury to have someone come to my house and ring the doorbell and say 'Right, let’s get moving'."

Sounds costly but it really works and can be a short term kickstart to a fitter you.

Natalie Portman: Go Vegetarian

"I actually went back to being vegetarian (from vegan) when I became pregnant, just because I felt like I was listening to my body to have eggs and dairy. If you're not eating eggs, then you can't have cookies or cakes from regular bakeries, which can become a problem when that's all you want to eat."

Research shows that vegetarians and vegans are less likely to be overweight and generally have lower cholesterol levels than meat eaters.

Davina McCall: Get On Your Bike

"Since Sport Relief cycling is my passion. I’ve got the whole kit, the padded shorts in every length, the helmet, all seasons wear; I am not a fair weather rider, I cycle all through the winter in the freezing cold. I love it; it is a great way for people in their forties and fifties to get great cardio but without the impact on their knees."

A cheap, easy and low impact way to get fit that works for all ages and all abilities.

Elle Macpherson: Do It Daily

"Doing regular exercise at a set time every morning is now a way of life for me. I am a creature of habit so I can get into the habit of doing it and not doing it. And once I break that habit for one or two days I find it harder to get back into it. I run and when I am on holiday I prefer to do sports like skiing, water skiing, hiking and surfing; sports for me are a great way of keeping in shape without seeming like exercise."

"The Body" knows that the easiest way to fit exercise into your life is to get moving every day, even if it’s just for 20 minutes. Do it for 30 days straight and it becomes a habit that‘s hard to break.

Tracy Anderson: Low Weights High Reps

"I never lift more than three pounds in my classes because no one wants to build muscle, what they want is to reshape a limb to be longer and leaner. That weight will start out feeling light but trust me when you have worked that arm through every angle and every muscle til it virtually fails then that weight works."

Tracey is the trainer to Gwyneth Paltrow. Have you seen Gwyneth’s body? Enough said, you know this woman knows her stuff.

Bar Refaeli: Mix It Up

"I don’t follow a strict regime but I do try to do something every day, whether it’s a full-on workout or maybe just a fast walk dong errands instead of getting in the car. I think it’s better for your body to do all different types of exercise as then you don’t get too used to doing one thing and you are always working out different muscles. Plus, it keeps you interested."

The model may be blessed with great genes but she also knows that a combination of cardio, weight training and sports is best for her body.