Violet Saunders is astounded when her boyfriend gets down on one knee and proposes. But at size 18-20, the thought of finding a wedding dress fills her with horror. What she needs is a miracle wedding day diet.
So when a leaflet advertising a new diet club - New You! - that drops through her letterbox, it seems like her prayers have been answered. But the club is run by the terrifying Trudie, who secretly despises her fat clients, while pretending to encourage them. Things go from bad to worse; everyone just gets fatter on the horrible New You! drink shakes. At work, Violet's half-Italian boss - a man with a lively sense of humour - looks on in amazement and finally persuades her to take a break from New You! and lunch with him at his family's delicatessen.
Inspired, she persuades her fellow dieters to form a new club, with secret weigh-ins at her house - while pretending to Trudie, of whom they are all petrified, that it is the New You! diet which is transforming them.
Fabulous Italian recipes gradually begin to work their magic, but can Violet the duckling really become Violet the swan in time for her wedding?