@Alisonjane10
I'm curious how you felt the day after your binge day?
The reason I ask is that if I go above a magic number of carbs, I get carb cravings. It's a sort of restless gnawing around the inside of my ribs. A restlessness. A distraction. And I find myself thinking about all those glorious mounds of mash and family sized Dairy Milk bars that are just whispering my name...
If you don't get carb cravings, then the odd binge will do you no more damage than any sudden rise in BG (and I don't think it is possible to measure it in such detail)
But if you DO get carb cravings then a single binge can be very difficult to get over. A single carb fest can lead to a seesaw of cravings, binging, cravings, binging...
We've had people come to the forum deeply distressed that a single wedding breakfast, or special birthday meal led to days, weeks and months of out-of-control eating.
So my answer to your original post is basically - it depends.
But I think it depends on whether you get carb cravings, or not. Because that is (IMHO) the deciding factor on whether occasional treats work for you, or not.