Season 4

This week's houseguests are 44-year-old Ian Miller and 36-year-old Sharon Prendagast.

Businessman and farting fiend Ian weighs in at 280 lbs. He's a far cry from the man he was eight years ago; he is now a staggering 130 lbs overweight. Ian spends a lot of time on the road, but even more time eating, especially chocolate and meat in the form of sausages, bacon and kebabs. All this eating leaves Ian with an insatiable thirst and there's only one thing that can quench it - milk, and gallons of it. Ian drinks a heart-stopping 20 containers a week, and his constant gorging has a very un-fragrant side effect - terrible flatulence, which doesn't exactly make him very popular with his friends and family. Ian knows he needs a change and dreams of running a marathon or at the very least, being around for a few years longer.

Mother of two, Sharon, spends most of her day preparing and eating food, so it's little wonder that she's more than 50 lbs overweight. Her widening waistline line is a result of her wandering hands - when she's around no-one's food is safe. With constant headaches, chafing thighs and huge elasticized trousers, Sharon knows she needs help. So along with Ian, she's bunking down with Gillian. But how will they cope under her watchful gaze, with no escape from that beady eye?