Tonight: Diet Fact, Diet Fiction?

Catherine Tyldesley investigates the pressure to have a perfect body and attempts to separate dieting facts from the myths. The Coronation Street star - once a size 22 and now a healthy size 12 - looks at the rocketing levels of obesity in Britain and the emerging attitudes of people who want to lose weight or just have a healthier lifestyle. But, with thousands of books and websites offering advice, just who and what should be believed?