In a diet special, the pound-for-pound test of 2017's biggest-selling diets comes to an end as the one providing most value for money is revealed. Dr Ranj Singh talks to an expert who believes that paying dieters to join slimming clubs could end up saving the NHS a fortune, while Sian Williams investigates if spending money on buying bottled water is simply pouring money down the drain. The programme also investigates whether the new recommendation of eating ten pieces of fresh fruit and veg a day is realistic and financially viable.