The aspect of this that involves morality is, I think, deeply Protestant. Or it's related to the kind of Protestantism that took root in Britain, anyway. A cynic might say that the punitively high taxes we have on tobacco, booze and now sugary drinks aren't really intended to curb our consumption of them at all, but are just a way of raising revenue that's seen as more morally acceptable than simply raising taxes across the board because they single out behaviours that are considered "sinful", or at least "naughty".
The sugary drinks thing is very revealing, actually, because I think it applies only to drinks with added sugar, meaning fruit juices are exempt even though many of them contain more sugar than Coca-Cola.
And the duty on petrol and diesel is just a modern extension of the idea of "sin" to include the environment. I wouldn't mind it being so expensive if we had trains and buses that were competitively priced, but we don't. If you drive to work every day then you can't just decide not to because a litre of fuel has gone up by 10p. You're just that bit poorer at the end of the month.