flat coke,bananas,rice,no diary products etc all old wives tales,for d&v the best and quickest cure is nothing but clear fluids ie water and soluble paracetamol and then be prepared to let it run its course anything from 24 to 72 hrs is usually the norm,if it goes on longer than that you would want to be seeing the gp as its likely that its caused by something a bit more than the usual gastroenteritis.