It's not just a word though, it's a word applied to small children, not adults, for anyone to apply the word 'naughty' to their activities as an adult is not taking responsibility for their lives.
Ohh - I've been a bit naughty - I've eaten a cream cake
Ohh - I've been a bit naughty - I've stolen from the till at work
Ohh - I've been a bit naughty - I've let the gardener shag me up the arse whilst DH was at a conference.
Adults aren't 'naughty', adults do things because they chose to do them for whatever reason, negative behaviours in adults aren't 'naughty', they are what they are.
And eating chocolate a few times a week can't even be classed as a negative behaviour, just part of a normal eating pattern.
So yes, the word naughty, when applied to food, or any decision I make as an adult 'ruffles my feathers', I'm smoking a cigarette as I type, it isn't naughty, it's just something I do. I smoked crack once many years ago, it wasn't the best choice, but it wasn't naughty, stupid yes, naughty, no.
Don't infantillise, own your choices, you're not a fucking kid. It's no-one else's fault.