Most people know that they shouldn't be eating the convenience food that's so readily available in shops and supermarkets, but they don't know how to break the habit. You don't need someone to tell you the damage that putting away numerous biscuits and chips will do. You want someone to show you how it's done.
As a woman who has conducted a very scientific research project into the inner psyche of sexually active blokes (i.e. has shagged around a bit) I say, with the sort of confidence normally reserved for Adele when she's telling Karl Lagerfeld to do one, that no man has ever seen me in a thong and then changed his mind about putting his willy inside of me. Never.