Well said. If you can’t find a way to be happy and satisfied with your new way of eating and lifestyle, of course the pounds will slowly creep back. But if you truly do enjoy eating better and being more active, it can be self-sustaining.
To answer the question: But OF COURSE.
People don’t have the conscious mental capacity to do what you describe, because the brain/body is working 24/7 against them. It never tires. It is wired and chemically inclined to push you to eat, eat poorly and it tirelessly tries to get you back to your heaviest weight and to continue the curve upward of weight gained that you’ve programmed your body for.
You must be a virtual medical freak to beat what your own mind and body are programmed to do.
Even if you stand there with the intention – the sheer passion – to begin a journey for life… doesn’t matter over the long run. I’ve seen the eye of the tiger in people, the absolute “I AM ON A MISSION TO CHANGE MY LIFE” attitude.
It fades. Over time. It just does.
. Except for the occasional medical freak.
Wait, is the assertion that everybody who has attained a certain weight at some point is more or less physiologically doomed to go back to it? Like, Matt Damon and Robert De Niro screwed themselves biologically by gaining 30 and 60 pounds respectively in The Informant and Raging Bull, and will now forever be engaged in a futile struggle to keep from returning to those weights? 
You’ve actually hit on a key component, because the folks in question forced themselves to that weight, and weren’t there very long. If you could grade the likelihood of them regaining it (or graph it), they wouldn’t have the doom/gloom odds of regaining it. They are exceptions. They didn’t take the normal course that overweight/obese people have taken… because they’ve not been heavy enough for long enough to recode their bodies, and they weren’t even coded to get to that weight in the first place.
I was just mourning the death of Owsley Stanley, infamous producer of high quality LSD, and I noticed an interesting commentary on his diet. Personally, I think his health was due to all that LSD.
[QUOTE=Wikipedia]
Stanley believed that the natural human diet is a totally carnivorous one, thus making it a no-carbohydrate diet, and that all vegetables are toxic. He claimed to have eaten almost nothing but meat, eggs, butter and cheese since 1959 and that he believed his body had not aged as much as the bodies of those who eat a more “normal” diet.
[/QUOTE]