New series in which the effects of various foods on the human body are revealed using experiments on volunteers. Fiona Bruce begins by joining nine fast-food addicts as they devour half a ton of raw fruit and vegetables in an enclosure at Paignton Zoo, and discovering how to reduce cholesterol and blood pressure without using drugs. She also tries the Evo diet and finds out whether prebiotic vegetables have the same beneficial results as the commercial probiotic yoghurts.