Documentary series following couples who are locked in a cycle of overeating that threatens not only their health but also their relationships. Celena has put on five stone since falling in love with Pete. He does all the cooking, and Celena can't get enough of his high-fat, high-sugar food. But her weight stops them from enjoying themselves - Celena won't go on holiday, have their son christened or marry Pete. Clinical psychologist Professor Tanya Byron and her team separate the couple for ten weeks in a bid to overhaul their habits. While fitness expert Rick Shakes-Braithwaite puts the two on bespoke diet and fitness plans, Tanya delves into the psychological patterns that keep Pete feeding the woman he loves and stop Celena loving the woman she is. She uncovers the source of Pete's hatred of vegetables, and while behavioural scientist Professor Paul Dolan attempts to retrain his taste buds, Tanya finds out how Celena's bad body image is getting in her way.