The first stage in the plan lasts two weeks. During this fortnight, you reduce your calorie intake to 1200. You also follow Rosemary's gentle exercise plan.
As well as eating less, the recipes Rosemary plans out for you are low-fat and low-GI which means you'll end up storing less fat (and therefore weight) and you'll feel fuller for longer. You're also not allowed to drink alcohol during this first stage as it contains what Rosemary describes as 'empty calories'.
The second stage also lasts a fortnight and for this you're allowed 1400 calories a day, including the occasional drink and naughty treat!
The final stage is about maintaining the weight you've lost. You do this by discovering your ideal calorie intake by taking into account your current weight and height. By sticking to this you'll keep the weight off.