The X-Factor
Jessica Biel keeps her body buff with a revolutionary high-impact workout called Xflowsion. Based on a blend of martial arts, complicated yoga poses and energetic dance moves to an upbeat soundtrack, this fat-blasting exercise class burns over 500 calories an hour!

Star Style says: It's said to be so addictive you'll be hooked after just one session, but this high-octane, body-shredding workout is not for the faint-hearted. Be prepared to sweat bucketloads and ache like mad the day after - but it's gotta be worth it for a Biel-style bod, right?

Green Day
With such a hectic schedule forcing her to eat on the go, size 10 pop star Pink sets aside one day a week to detox. She bans anything except green foods (which are chock-full of vitamins and minerals) and munches on mangetout, spinach and broccoli for every meal. Pink's trainer, Gregory Joujon-Roche, says, "Start the day with an apple, celery and cucumber smoothie and green grapes, have salad for lunch and steamed veg for dinner."

Star Style says: Detoxing one day a week will do no harm to your health, in fact, it's a good way of flushing any toxins from your body.

Stay Fruitiful
Rihanna credits her low-calorie diet for maintaining her amazing shape. "I have egg whites and pineapple for breakfast, washed down with hot water and lemon," says the svelte singer. Acidic pineapple is said to help stop the absorption of fat, whilst hot water with lemon helps to cleanse the body first thing in the morning.

Star Style says: Ripe pineapple can help curb sweet cravings, and is jam-packed with vitamin C and is low in fat and cholesterol, while a cup of hot water with lemon first thing releases enzymes that help kick-start your metabolism. How virtuous!

Where to go
She's not called sporty spice for nothing! Mel C keeps her size 12 figure trim through high-intensity workouts every morning. She kick-starts her metabolism by exercising on an empty stomach, then, afterwards, fills herself up with a whey protein drink to stabilise her blood sugar levels, curb cravings and kill hunger pangs until lunchtime.

Star Style says: Light exercise on an empty stomach uses the energy from the night before to fuel your workout - meaning you're likely to burn stored fat. Just don't over-exert yourself, and keep hydrated throughout your workout.

B A Pill Popper!
Ever wondered how Penelope Cruz looks happy, glowing and wobble-free? She pops a vitamin B pill each morning to curb her sweet cravings and lift her mood, and insists, "I can't live without my Bs."

Star Style says: Whilst taking vitamins in moderation won't harm your health, mega doses (Hilary Swank is said to take up to 45 a day!) could be dangerous. Instead, munch on mood-lifting Brazil nuts, blueberries and broccoli for a natural vitamin high.