New series. 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, Caroline and Charmaine have a week to slim down for a spa day, David and John go on six-week plans to lose weight for a friend's wedding, while Karen and Tracey want to get in shape for a summer holiday in three months' time. Plus, Helen finds out how vision affects appetite.