You don’t have to “go off the diet” because it’s a special day or a holiday. And there’s no need to “get back on the diet” once it’s all over. A healthy diet is not on or off.
Some overarching guidelines might be helpful. On most days aim to keep most of your meals healthy, nutritious and delicious. And some meals on some days can land on the far indulging-side of the continuum.
Then, there are the odd days when most meal are a closer to indulging than nutritious. That’s fine too. Even expected. That’s life.
Besides, even if you’d only eat chocolate all this weekend, it makes little difference in your long-term progress when eating somewhat healthy and nutritious most, not all, of the other times.
The end goal is to live on a continuum where everything is allowed. Even better, every food is allowed guilt free and with pleasure. It’ll take practice and determination to shatter some long-held beliefs about the foods you eat. But it’s a place worth striving for.