Xand van Tulleken and Helen Lawal oversee proceedings as three more pairs road test some of the most popular and talked about diets. Newlyweds Steven and Eamonn have eight days to trim down ahead of their holiday, friends Valetta and Paulette go on six-week diets to slim before their friend's wedding in the sun, and drinking buddies Sian and Keighlee want to lose weight for a girls' holiday in four months' time. Xand investigates whether people's hormones can make them fat, and Helen examines whether knitting can lead to weight loss.