A brand new series of this show that sees doctors tackling some of the topical issues of the day. This opening episode sees them investigating the best way to keep calories in check - dieting or exercise. They do say that the pounds are lost in the kitchen, so just how much use is the gym to us? Also tonight, Saleyha Ahsan looks into whether probiotic products can improve health, Chris van Tulleken discovers whether red wine lives up to its healthy reputation, and Gabriel Weston witnesses a sternum implant operation carried out using 3D printing - the first procedure of its kind in the UK.