I don't do it regularly, but I occasionally eat small quantities of nostalgic foods on special occasions. For example, I could not go through Thanksgiving without eating a little pumpkin pie. However, I decided it was really the pumpkin that I was nostalgic for, not the crust, so I ate only the inside of the pie

For me, the important thing is to plan in advance what I am doing and make sure that there are lots of lowcarb foods available at the same time. That way, I don't have any problems controlling the quantity of the high carb food I eat. Also, I think that having lots of protein and fat in your system helps mitigate the effect of eating carbs on your blood sugar. At Thanksgiving, I filled up on turkey and vegetables, so that when the pumpkin pie came around I was satisfied with a small piece.

Exercise is always a good thing for burning up extra carbs. I took a walk Thanksgiving morning and a long walk the day after Thanksgiving. Despite having some pumpkin pie, as well as some squash that had molasses in it, I did not gain any weight.

The really dangerous cheats are the unplanned ones when you are very hungry. An occasional (occasional does not mean once a week!) planned cheat on a special occasion (birthday or holiday) can probably be incorporated into your eating plan. However, each person is unique, so you'll have to determine for yourself if eating even a few extra carbs creates cravings and therefore problems for you.