The UK has the highest level of obesity in Western Europe, and in response a billion pound dieting industry has sprung up with a glut of advice on how to lose weight. But there are questions over the effectiveness of some diets: are they based on myths rather than science? And could some diets lead us to cut out important food groups? In Tonight’s programme, Diet Fact: Diet Fiction, Coronation Street’s Cath Tyldesley investigates the diet industry. Cath, who plays the fiery Eva Price in Coronation Street, knows what it’s like to have your image and appearance constantly scrutinised by the public and the media. She’s now a healthy size 10 but back when she was 17, she was a size 22. In Tonight’s programme, Cath meets David and Beverley, who are trying a new programme commissioned by Oxfordshire County Council. Both David and Beverley are currently obese, and have had little success with other diets. However, their current programme aims to deal with their psychological relationship with food, which could help them maintain weight loss. To wade through the mountain of conflicting information on what we should and shouldn’t eat, Cath consulted expert Tim Spector, a Professor of Genetics at Kings College London. After a personal health scare, Tim decided to research into diets, dieting and food.