I think starting over is an illusion. Because whatever you did before "starting over" is still with you. You don't get absolved of the consequences. Your "last" binge isn't a calorie-freebie
I think the concept of starting over messes with our heads in at least a couple ways: (1) It makes us rationalize things like the aforementioned last binge before starting over; (2) We never get the strengthening experience of seeing things through. When you start over, you're either leaving behind the good or denying that there was any good. Neither serves you well. You can have, say, the experience of a year of ups and downs and learning; or you can have the experience of 7 short-lived diets that ended in failures.
"Starting over" can still be a useful tool, giving you the energy and motivation to get started. But it can be a dangerous tool, enticing you to always be dumping your "failures" and starting over, and never really owning all your reality. In that respect, "starting over" is just an act of deferring pain - the pain of facing and owning all your reality. It's a only a deferment, you have to face it eventually. Maybe that's a bargain that will serve you well, maybe it's not. Obviously, if it's happening over and over, it's not serving.