Well isn't that just the 64 million dollar question? Third and final episode in this second series of How to Stay Young, which sees Angela Rippon and Dr Chris Van Tulleken team up with scientists to demonstrate what can be done to reverse the ageing process. Tonight, they meet 45-year-old Tina Collett who discovers the damage her diet is doing to her skin, and ex-policeman Rich Jones scores the worst body age seen on the programme so far. Elsewhere, 68-year-old Isabella McTaggart learns how to reverse her brain's decline.