In episode 1 we meet Becky and her partner Phil who are locked in a cycle of over-consumption that now threatens their relationship. Knocking back three litres of fizzy drinks a day, Phil's weight has yo-yoed from 15 to 30 stone, twice, whilst Becky caves in to any takeaway temptation.Clinical psychologist, professor Tanya Byron and her team - fitness expert Rick Shakes-Braithwaite and Paul Dolan, professor of behavioural science at LSE - separate them for ten weeks in a bid to overhaul their habits. Phil discovers he has life-threatening blood pressure and the realisation hits him that without change he won't live to see his children grow up. While Rick guides Phil back to exercise to improve the health of his heart, Becky finds that the main thing getting in the way of sustaining her weight loss is a chronic lack of confidence. But half way through the programme, inexplicably Phil begins to resist the help. Tanya calls in behavioural scientist Professor Paul Dolan for radical mind-training.