Xand van Tulleken and Helen Lawal oversee proceedings as three more pairs road test some of the most popular and talked about diets. Sade and Becky have two weeks to slim down for a day at the races, Derek and Bruce go on four-week dieting plans ahead of a summer barbecue, and Sam and Fay want to slim down for their annual bus drivers' picnic in four months. Xand also investigates the latest liposuction techniques and finds out if unconscious persuasion can melt away people's fat.