Dr. Xand van Tulleken and dietician Hala El-Shafie ask ordinary Brits to road test some of the most popular and talked about diets out there, and to then give viewers the lowdown on how the diets worked for them. CafÚ cook Stacie Stewart helps the volunteers to turn their diets into delicious dishes. The second series begins with Emilie and Harriet, who have two weeks to slim down for a photo shoot. Cousins Natasha and Chiquita go on a six-week diet for Natasha’s wedding. And brothers Gary and Wayne want to slim down for a darts competition due in four months. Xand also investigates how exposure to extreme temperatures can affect weight loss and finds out if chewing for longer can help the calorie count.