I have a few rules around special occasions.
We don’t really celebrate Easter or Xmas, but I will allow myself a mince pie but only if my dad has made them. Shop bought ones don’t do anything for me in comparison. If dad doesn’t make them, I won’t bother. Sky hasn’t fallen in yet.
I don’t like milk chocolate but will have a bit of 90-100% dark chocolate a couple of times a month, when I really want it. We don’t celebrate Easter and DD only gets a couple of milk chocolate eggs so it’s not an issue for me.
Birthdays, again l, I might have a small piece of cake if it’s something worth having. Generally I find shop bought cake disappointing so I will swerve it.
I absolutely allow myself choice. If I want something sweet, or 12 gins on a work night out I’ll have it, and deal with the consequences as anyone would a hangover. But over time it becomes easier to pay attention and think “I could have it if I wanted it, but actually I’d prefer to have more energy tomorrow”. “I don’t eat that” is a really powerful statement for me and to explain to others, in exactly the same way you would tell them you don’t eat meat, or smoke, for example.