Diary of a dieter: week 1

Journalist Rachel Roberts talks about the changing room horror that made her determined to lose weight

When it comes to losing weight, everyone has their own personal turning point - that moment when you know you have to do something about your ever-expanding body.

For me, the crunch came a few weeks ago during a particularly frustrating shopping trip. I've always loved clothes, whatever size I've been. I felt a bit like a child in her mother's dressing-up box, as I grabbed a selection of beautiful clothes to try on.

But my excitement fizzled out when I realised that none of the clothes (most of which were size 16) fitted. In fact, the only thing I could find that got anywhere near was an awful, sludge-coloured, baggy skirt. I could have cried.

Of course, I've tried things on in the past before having to put them back on the rail. Who hasn't? But this time the penny dropped. I felt disappointed about not being able to buy the clothes, and disgusted that I had let myself get this far.

It was there and then that I promised myself I'd never buy a size 16 again. My weight has been creeping up slowly for the past three years - the result of steady comfort eating, after giving up smoking, the break-up of a major relationship, and the death of my beloved grandfather.

I was a size 12 before everything began to spin out of control. My friends always think of me as a happy, together person, and I have always remained positive, regardless of my size. But now I have realised that being overweight is robbing me of my confidence. It's all very well being happy on the outside, but when you are not happy on the inside, it's time to do something about it. For me, being a size 16 feels wrong. I feel too big.

That's why I joined Weight Watchers. I chose this diet because I had joined them before (about five years ago) and lost 17lbs in two months.

My first weigh-in was pretty horrific - I am 30 and 5ft 5in tall. Watching the scales shoot up to 13 stone 7lb didn't do much for my confidence. However, knowing that I was finally taking control made me feel good.

Liz, our group leader, explained how the diet works. Each food is assigned a number of points, depending on its calorie and saturated fat content. I'm allowed 22 points a day and, best of all, there are no forbidden foods. It's entirely up to me how I use the points. For six points, I can have a low-fat Marks and Spencer chicken dinner or a Wholenut chocolate bar.

Liz's positive attitude outweighed my horror of finding out just how much weight I needed to lose (at least two stone; three if I'm brutally honest).