Becky and Phil knock back three litres of fizzy drinks a day, Phil's yo-yoed between 15 and 30 stone twice, while Becky caves in to any takeaway temptation. Clinical psychologist Prof Tanya Byron and her team separate them for ten weeks in a bid to overhaul their habits. Phil discovers he has life-threatening blood pressure and the realisation hits that without change he won't live to see his children grow up. While fitness expert Rick Shakes-Brathwaite guides Phil's heart back to health through exercise, Becky finds that the only thing getting in the way of sustaining her weight loss is her chronic lack of confidence. But halfway through the programme, Phil inexplicably begins to resist. Tanya calls in behavioural scientist Prof Paul Dolan for radical mind-training, while she gathers his family for a different tack.