Thank you both for your comments. Sugar is best avoided but it is often in fruit drinks as well as the fizzy (carbonated) kind. Some no doubt have more sugar than others, or artificial sweeteners, etc. As you say, heathfield, there's not a lot to be said for 'fizzies', but I doubt if they are really such an evil junk as they are made out to be.
fizzy drinks are made fizzy by the addition of carbon dioxide. This aid in teh corrosion of your teeth, and so does the sugar. A 330ml can of coke has 8 spoons of sugar in it (or equilivant of) while red bull has 15 spoons of sugar....i think its the amount of sugar that surprises people