Doctors Xand van Tulleken and Helen Lawal oversee proceedings as more people attempt some of the most popular and talked about diets on the market today, while cook Stacie Stewart gives advice about recipes. In the opening edition, Laura and Gellner have two weeks to slim down for a spa day, sisters Aishia and Karlette go on six-week diets for their joint birthday party, and truckers Adain and Gerry hope to lose weight for a hot-tub party in four months' time.