Dr Christian visits McAllen's mortuary, which is having to be supersized to cope with wider doorways and autopsy tables. In the feeding clinic, LJ Marley, a takeaway addict who tips the scales at 24 stone, with a 59 inch waist, swaps diets with Katie Reeve, whose childlike portions see her weigh in at a paltry 6st 11lb. LJ visits the US for some shock therapy, being forced to face up to the damage his eating habits could be doing to his body. And Emma Woolf reveals how she developed anorexia and lost half her body weight after a break-up while a student at Oxford.

In the feeding clinic this time Joanne Leadley goes head to head with Ross Clarke from Cardiff. Ross is a meal dodger who never finds time to eat, while 41-year-old Joanne is a giant-portion gorger. Their swap is packed with drama, tantrums and tears. Dr Christian shows Ross the damage his diet is doing to his body and sends Jo to Georgia, America, to meet a woman whose life has been destroyed by overeating. Dr Christian visits America's fattest town, where he meets doctors who treat a huge variety of obesity-related illnesses and patients who have lost toes, limbs and even their eyesight. Recovering anorexic and journalist Emma Woolf explores whether anorexia is inherited.

Forty-two- year-old super snacker Julie Menzies swaps diets with 24-year-old fussy eater Zoe Hughes-Blinston in an emotional encounter. Dr Christian discovers how the funeral parlour in America's fattest town copes with bigger and bigger bodies. And journalist Emma Woolf investigates the little known world of male eating disorders.

Facing off in the Feeding Clinic is 24-stone takeaway addict Craig Nellies and superskinny cola addict Simon Tacaks, who's just too lazy to bother to eat. Dr Christian shows skeletal Simon how concentrated amounts of the chemicals found in cola can cause extreme damage to teeth. In America's fattest town, where levels of obesity-related diabetes have hit epidemic proportions, Dr Christian visits a patient suffering chronic wounds and organ damage. Plus, former anorexia sufferer Emma Woolf investigates anorexia during pregnancy.

There's a tense and emotional swap in the feeding clinic as teenage comfort eater Victoria Madden goes head to head with fussy food avoider Hannah Pidgley, whose picky eating has already led to her being diagnosed with malnutrition. Hannah's terrified that her terrible diet is wrecking her fertility and her dreams of being a mum, while student nurse Victoria's huge meals and non-stop snacking sees her tip the scales at a mighty 19st 12lb. Dr Christian visits an American women's hospital to find out how obesity affects pregnancy and birth. Emma Woolf looks at eating disorders in older women.

Twenty-stone comfort eater Julie Henry swaps diets with coffee addict Dougie Reid. Emma Woolf explores the importance of the early diagnosis of eating disorders. And in America, Dr Christian takes a ride on a bus that's helping Texans battle the bulge.

It's all out war as round-the-clock snacker Emma Cain goes head to head with Robert Musgrove, who can't be bothered to eat. Dr Christian shows lager-guzzling Emma just what her favourite tipple is doing to her body. In America's fattest town he visits an after-school scheme that aims to help combat childhood obesity. And Emma Woolf travels to Holland to investigate online therapy in the treatment of eating disorders.

Pizza delivery driver Thomas Barnes weighs 27 stone 10 lbs, largely due to his weakness for pizza. Glamourous granny Linda Chik loves fruit and veg, but doesn't eat enough for her busy-bee lifestyle, so weighs in at only seven stone. Before they swap diets, Dr Christian prescribes a supersized wake up call for Thomas - sending him to visit 35 stone Robin Jones from Missouri. Robin is registered disabled and suffers from a host of health problems due to her obesity. And Emma Woolf concludes her investigation into eating disorders with a meeting with 21-year-old Aria Valzano who developed anorexia aged 14.

The show revisits three of last year's feeding clinic inmates - meal dodger Nathan Smith, takeaway king Chris Longley, and convenience queen Jo Palmer. One year on, have they managed to ditch their dreadful diets for good? Plus, it revisits Dr Christian's time in Evansville, Indiana - the US city that topped the polls in 2011 as America's Fattest. At the local Deaconess Hospital, he meets patients suffering the severe effects of obesity, and staff on the front line dealing with the crisis.He also visits Keith Davis from Goliath Caskets, who knows all about the ever expanding population - because he makes the biggest coffins in the United States. Twenty-four stone 6 Chris gorged on up to a dozen takeaways a week. His body was paying a very high price when he checked in to the Feeding clinic. Sharing the diet swap dinner table with Chris was 21 year old meal dodging hairdresser Nathan Smith - who had a head full of excuses for his puny 8 stone 5 frame.

The show catches up with sugar fan Hayley Payne and snackaholic Geoff Milton, one year after they met in the feeding clinic.