You Are What You Eat has just got bigger as Gillian McKeith is back with a brand new series of hour-long episodes. The dinky diet detective has traveled the UK holding open auditions to find more desperate cases, and now she’s found them, they’ve got a very big shock in store!

Over the years she’s shouted at the overeaters and condemned the under exercisers, but now the chunky monkeys are moving in! They don’t know it yet, but the McKeith treatment means living under her roof, and following her house rules, with no escape! To make matters worse, Gillian will even invite herself to stay at theirs if they fall off the wagon.

Each show is crammed with as many nutritional tips as ever as Gillian pushes her skills to the limit with more shocking demonstrations of the dastardly effects of our dietary habits.

This week’s houseguests are 44-year-old Ian Miller from Yorkshire and 36-year-old Sharon Prendagast from Merseyside. Businessman and farting fiend Ian weighs in at 20 stone. He’s a far cry from his slim-figured self of eight years ago, and is now a staggering nine stone overweight.

Ian spends a lot of time on the road, but even more time eating, gobbling up Turkish delight and scoffing meat in the form of sausages, bacon and kebabs. All this munching leaves Ian with an insatiable thirst and there’s only one thing that can quench it: milk. Gallons of it: a heart-stopping 20 pints of the white stuff a week!

Ian’s constant gorging has a very un-fragrant side effect – terrible flatulence – and his family and colleagues despair of him. Ian himself is tired of his tyres, and dreams or running a marathon or at least being around for a few years longer.

Child-minder and mother of two Sharon spends most of her day preparing and eating food, so it’s little wonder that she’s more than four stone overweight. Fifteen-stone Sharon’s appetite doesn’t just stop at her own plate. Her widening waistline is a result of her wandering hands, and when she’s around no-one’s food is safe. Be it her own children’s lunch boxes, or dinner for the children she child-minds, she just can’t help the odd morsel for herself.

With constant headaches, chaffing thighs and huge elasticated trousers, Sharon knows she needs help. So along with Ian, she’s bunking down with Ms McKeith. But how will they cope under her watchful gaze, with no escape from that beady eye? There’ll be no nursery teas or hot milky drinks at bedtime chez McKeith. It’s lentil stew and kale juice all the way. And if Ian thinks she’ll tolerate any bottom burps in her palatial home, he’s got another thing coming!

The new series of You Are What You Eat launches on Channel 4 on Tuesday 9 January 2007