"I look at my body mass index (BMI) instead of my weight. My BMI is always around 23.4, which tells me I'm a healthy weight for my height, 5'8" – over 25 and I'd be overweight. I want to be a good role model for my daughters, Tallulah and Melissa, and I'll do that by looking at my health, not my weight. 'My body craves sugar in any shape or form and I have to work to avoid desserts. If I had the choice, of course I'd have banoffee pie, but instead I have, say, a bowl of strawberries, maybe with a little sweetener and vanilla yoghurt. I also had to really concentrate on exercising hard – just for a short period – to get back to my stable weight after I had my second daughter in 2007. I needed motivation, so I hired a personal trainer – they'll come and bang on your door so you can't duck out and you don't want to waste time when you're paying for it. We ran for half of the time – and you can't slack when you have someone running beside you – and did circuit training for the other half. And I'd do lunges across the length of a football field. By doing one intensive hour, three times a week, I only needed eight weeks to get back in shape."