Pizza delivery driver Thomas Barnes weighs 27st 10lb, 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 by meeting with 21-year-old Aria Valzano, who was 14 when she developed anorexia.