Eighteen-year-old William, who is autistic and has eaten the same lunch of burger and chips every day for two years, goes on a tailored diet to reduce his calorie intake by half.

Sixteen-year-old Anna from Warrington weighs in at almost sixteen and half stone and her appetite has got out of control, while mum Sarah is the perfect partner in crime.

Cleo is 16 and weighs in at just over 23 stone thanks to a diet of freezer food and fizzy drinks, but she and her family change their lifestyles to try to halt their weight gain.