Pint-sized Tiffany Patterson had to grow up quickly when her mum left home, leaving her to become the breadwinner and meal-maker. Too busy to eat, the seven stone 25-year-old lives on a daily dose of energy drinks and little else.

Joining her for the five-day diet swap is DJ Keith Kelsey, whose out-of-hours eating has caused his weight to balloon to 30 stone. Dr Christian Jessen accompanies him to see 45-year-old Lisa Wheeler as she undergoes life-threatening weight-loss surgery.

It's ping pong in exchange for pizza as Anna Richardson takes on the Flab Fighters with a game of table tennis to show them how to have their favourite treats and still lose weight.

Plus four young women battling with anorexia nervosa face their food fears in the kitchen of a gourmet curry house, where they have to prepare and eat a highly calorific meal.