Super snacker Julie meets fussy eater Zoe. And in America's fattest town, Dr Christian sees supersize coffins for supersize corpses needing two burial plots.
Supersize Vs. Superskinny Season Kids
15-year-old Ieuan Rosser, who weighs 17 stone, and 13-year-old Jess, who weighs six and a half stone.
It's not an easy ride for Ieuan who is used to consuming a a shocking 4000 calories a day. Nor for his mum Kay who's forced to face up to why she hasn't been able to stop her son from putting on weight.
Meanwhile super fussy Jess's inability to try new healthier foods is put to the test. But can laidback dad Dave finally do what he should have done years ago and put his foot down when it comes to his daughter's unhealthy diet?
But it's not just Mums and Dads who need to take responsibility for their children's diets, and so Dr Jessen's on a mission to get the nation's kids to take charge of what they put in their mouths too. Using actual samples of human bodies, he delivers the first of four hard-hitting lectures to a group of junk-loving school kids on the strain that eating too much or too little puts on the heart.
The Supersizers get a glimpse into what the future might hold as they watch personal video messages from America. Fifteen-year-old Hayli Cohen from New York state weighs in at a hefty nineteen stone. Allowed to eat whatever she wanted after her parents divorced when she was three years old, Hayli's weight soared. She's even resorted to having a gastric band fitted - something Ieuan is also considering. But will her experience and words of warning give him and Mum Kay the push they need to sort out his diet for good?
Louise vs Delroy
Journalist Anna Richardson nips across the pond to New York City where she discovers the very latest fat-busting techniques, including cheerleader aerobics!
Dr Christian Jessen faces a bumpy ride in the feeding clinic as superskinny size zero Louise Sapsford, who clocks in at 6 stone 2lb, faces up to supersize 28 stone 13 pounder Desroy Gordon's challenging diet of non-stop take-aways.
Louise comes to terms with the fact that size zero is not a good look and changes her eating habits for good. Stuffing herself with Desroy's gigantic meals and a relentless run of take-away dinners teaches Louise she can eat more than the tiny meals she never normally finishes.
Gillian McKeith has a powerful arse-busting technique in store for some London lasses as she continues her quest to reduce the nation's rears. She also finds out if a bunch of jive dancers know their calories as well as their moves as she offers them a variety of romantic dinners for two. Can they tell which dishes they can dine out on without building up their love handles?