Doctors Helen Lawal and Javid Abdelmoneim help people try out the most popular diets on the market, with participants being put on a variety of regimens. Sisters Lesley and Debra from Essex road-test diets followed by celebrities Adele and Rebel Wilson, while friends Temi and Bose try out intermittent fasting, and drinking pals Maurice and Mick want to lose weight before attempting a Three Peaks walk in their native Yorkshire.