The Castle family from Welwyn Garden City are mystified - how can they be putting on weight when they eat mostly healthy, home-cooked food? Using surveillance from cameras in their home, plus private investigators following them outside the house, the Castles are shown what they're really eating. Anna Richardson is on hand to guide them through their discovery, as well as put them on a ten-week healthy-eating regime. Plus, a group of office workers test the theory that by putting sweet treats out of sight, they can be kept out of mind and - more importantly - mouth.

This week, Dawn and Mike, a married couple from Hull and their best friend and lodger, Gareth, want to solve the riddle of why they're putting on weight.

The Meakin family are under the spotlight this week. Mum Sue, daughter Natalie, and son Dave are all needing help to solve the riddle of why they're putting on weight.

The White Oliver family are desperate to find out how to live a healthier, more balanced diet for the sake of daughter Ellie who is very over weight.

Engaged couple Ronnie Derrett and Stuart Ellaway from Farnborough want to solve the riddle of why they're putting on weight.

Lovebirds Ray and Ange from Bolton are desperate to lose weight and are convinced they eat healthily. Ray's infamous 'pie butty' and belly-buster breakfasts suggest otherwise. Once they learn the shocking truth of what they're really eating, will they be able to stick to a five week eating plan, win their battle of the bulge and get their wedding back on track? Plus, the show lays some mischievous and tasty traps for the public, to prove just how easy it is for us all to succumb to secret eating.

Neither David nor Denise from Eccles thinks they eat enough to warrant their size and are convinced their diet is a healthy one. Ttheir passion for rich sauces and plentiful portions seem to suggest otherwise, as does David's determination to clear every last bit on his plate, despite having a gastric band. Once they learn the shocking truth of what they're really eating, will they be able to stop blaming each other for their ever-widening waistbands, stick to a healthy eating plan and win their battle of the bulge? And what will the cameras reveal from the mischievous and tasty traps set for the public that prove just how easy it is for us all to succumb to secret eating?

Sisters Lauren and Stephanie from Essex are 20something siblings mystified by their weight gain. They've each put on two stone over the last two years, tipping the scales over into the overweight category. Lauren is even training for the marathon but has yet to lose a pound. The girls think they eat healthily, but Stephanie's grab-and-go habits and Lauren's social suppers suggest otherwise. Once they learn the shocking truth of what they're really eating, will they be able to stick to a healthy eating plan, nip their weight gain in the bud and lead a healthier lifestyle in the future? Plus, when it comes to eating, once we pop most of us can't stop, so in this episode the secret cameras record mischievous and tasty traps set for the public, proving just how easy it is for anyone to succumb to secret eating.

Hetal and Mitul submit to a course of diet surveillance. Is it the extra cheese sauce in their moussaka or the added chocolate spread in their health shakes that's stopping them from losing weight?

Good friends Daryl and Kat from Essex are desperate to lose weight, but think they eat healthily. Daryl's breakfast blowouts and Kate's serial snacking suggest otherwise.

Sister and brother Emma and Matthew from Camberley in Surrey are under the spotlight this time. Matthew is very sporty, mountain-biking at weekends and going to the gym three times a week, while Emma restricts her food intake on weekdays to just a few hundred calories a day. So why are these two putting on weight? They're convinced they're making the right choices with their food, but Emma's habit of picking while cooking, and Matthew's willingness to indulge in chocolate cake immediately after exercise, seem to suggest otherwise. Once they learn the shocking truth of what they're really eating, will these siblings be able to stick to a healthy eating plan, start winning their fight with the flab and look forward to a healthier future?

Helena and Murray have been married for around 22 years, but their weight gain is concerning them. Helena believes that her weight gain is down to the menopause, but Murray is at a loss to explain why he's also gained weight. The surveillance cameras follow their every move to try and discover the truth.

Kelli and Tracey are both due to get married soon but are baffled by how they've managed to put on four stone between them since they met. They agree to allow surveillance cameras being put inside their home to monitor what they eat.

Sharon and Tracy are sisters from Birmingham and are unable to find a reason to explain their expanding midriff. Puzzled at. They agree to allow surveillance cameras being put inside their homes to monitor what they eat.

Lorraine and Cori are dieting mother and daughter from south London, whose massive weight gain is a total mystery to them. They agree to let surveillance cameras being put inside their home to monitor what they eat.

Glyn, Louise and Sue are 3 people whose family fortunes have increased by more than just a few pounds and they’re desperate to understand why they can’t shed their weight.

Lovebirds 22 year old Katie and 24 year old Michael from Kent are a young couple who can’t understand why they’ve piled on the pounds. Not only have they grown up together but they’ve also grown outwards and in the last 4 years they’ve put on a massive 8 stone between them. To find out why their weight is spiraling out of control Katie and Michael agree to surveillance cameras being rigged inside their home to monitor what they eat and in order to get the full picture they are also tracked outside the home by a crack PI team.

Allan and Emma have been together for around four years but their weight gain has made them both determined to solve the mystery of the extra pounds once and for all.

Sisters Precious and Florence, from Sidcup, are the latest pair to come under the show's spotlight with their eating habits held up for scrutiny. Gym bunny Precious works out every day and insists she eats healthily, while elder sister Florence cooks everything from scratch and would rather eat her own food than touch a takeaway. So why are they both putting on weight? They're convinced they're making the right choices with their food, but Florence's mega-carb portion sizes, Precious's love of a treat, and both sisters' devotion to fast food seem to suggest otherwise.

Siblings Jill Hamill and Stuart Raphel from the Wirral are in the spotlight. Both are desperate to lose weight, but convinced they don't eat enough. What will the five-day around-the-clock surveillance reveal? Once Jill and Stuart learn the shocking truth of what they're really consuming, will they be able to stick to a ten-week healthy eating regime, designed by an expert dietician, and win their battle with the bulge for good?

Since married couple Emma and Paul from Warrington got together they've piled on a massive seven stone between them, yet are still under the impression they eat healthily. However, Emma's craving for carbs and Paul's passion for potatoes - 16 in one sitting - suggests otherwise. Once they learn the shocking truth of what they're really eating, will they be able to stick to a healthy eating plan?

Faye and Laura are shocked by their weight gain as they've been working overtime in the gym in an effort to lose weight, but with little success. They are put under 24-hour-camera surveillance in the hope of finding out if their diets reveal any clues as to those puzzling extra pounds.