It's a first for the show with a double swap as mother and daughter Janet and Tara Wells swap diets with too-busy-to-eat Joanne Evans and Keith Linage.

Janet and Tara weigh in at nearly half a ton. Their diet of cholesterol-crammed Chinese meals and cakes aplenty have left them both morbidly obese.

Joanne and workaholic Keith have no time for food in their hectic lifestyles. But, with a gallery of superskinny horrors, Dr Christian shocks them into realising the potential dangers of their deficient diets.

And the show's group of eating disordered people bravely face their food fears head-on as they attempt to confront the overwhelming choices offered at a breakfast buffet.