You are right on two counts
This is it for life
So it has to be realistic
So for me my weeks looks like this
I have my crisps, white bread and butter and carbs - pasta and garlic bread on Saturdays, because those are the foods I have to avoid daily. Saturday - I dont give a poo - its weight in day.
Sunday Im straight back on plan , usually a roast dinner ( SW friendly ) and perhaps some scrambled eggs
And then that's me for the week, I know what's SW friendly, and I mostly make those choices. But then there are cock ups. Some mornings my stomach feels like my throat has been cut, Im in work, the choices are pastry or cake, so I will take something. That's fine once a week, 3 times a week then I skip lunches
For me it's not a hardship as Ive been here for so long. Yesterday for example, I was up at 4am, and ate my first meal at 7.30pm
Im not advocating that as healthy eating, Im just saying how it goes for me , even when piling on the weight I was never gorging, just eating the wrong things for me ( bread , crisps and pasta, little veg, no fruit, scarcely any protein or dairy ) . Now for 3 or 4 days a week Im eating from the correct food groups