Second-hand car dealer James Collier goes head to head with uninterested undereater Modasser Zafar in a tense diet swap. Thirty-two-year-old James loves supersized portions of greasy food - sometimes getting through four platefuls in a sitting. James weighs in at over 24 stone six and is terrified that his steady weight gain will end up giving him a heart attack and prevent him seeing his kids grow up. Thirty-one-year-old credit controller Modasser is at the opposite end of the scales at a tiny eight stone three. He skips meals and rarely finishes dinner. James receives a 32 stone wake-up call from America in the form of Mike Eak from Florida. Mike not only lost his job because of his weight but his enormous size has left him incontinent and his lack of mobility has meant he's taken to urinating in cups. Also, the remaining two members of the eating disordered group reach the end of the course and celebrate with a two course meal.

• Liza Tarbuck
• Anna Ryder Richardson
• Gillian McKeith