Pizza delivery driver Thomas Barnes weighs 27 stone 10 lbs, largely due to his weakness for pizza. Glamourous granny Linda Chik loves fruit and veg, but doesn't eat enough for her busy-bee lifestyle, so weighs in at only seven stone. Before they swap diets, Dr Christian prescribes a supersized wake up call for Thomas - sending him to visit 35 stone Robin Jones from Missouri. Robin is registered disabled and suffers from a host of health problems due to her obesity. And Emma Woolf concludes her investigation into eating disorders with a meeting with 21-year-old Aria Valzano who developed anorexia aged 14.