The new series starts with tears and tantrums as 21-stone Louise Hayes swaps with Josh Evan, whose diet barely features a proper meal.

Louise is determined to get through the swap as deep down she's terrified her five-year-old son is picking up her supersize habits and will end up as big as her. She gets a personal message from America, from 41-stone Texan Karen Ferguson, who is so disabled by her weight that she's been forced to move into a care home. Louise is also flown out to America to witness first hand the horrors of being super-obese.