I do seem to be an all or nothing person yes.
I am at my absolute heaviest and am desperate to get off to a good start. I do have a bad relationship with food.
I too cannot have just one biscuit/bag of crisps/cake/sweet/alcoholic drink. I find it easier to do without than just have one.
I've tried various diets in the last couple of years and need to get my head around what I'm doing this time as I get them mixed up.
When I cut out processed carbs my appetite dwindles and I do not need to eat a lot at all. Rather than going the Atkins type way I am allowing myself fruit and all veg apart from potatoes this time in the knowledge that it will be a more enjoyable way of eating and that I won't feel so deprived and so hopefully stick with it.