This might seem like a strange analogy but keep reading and it will make sense:
Have you ever heard of the frog and the pot of water?
If you placed a frog in a pot of water sitting on a stove and turned on the heat, the frog would end up getting boiled to death.
But if you had a pot of already boiling water and tried to put a frog in it, the frog would jump out immediately.
Now relate that to weight loss and gain.
Weight gain didn't come on over night. It creeped on and I put up with the stomache pain, the back aches, the head aches, being out of breath, etc., because it didn't seem like too big of a deal at the time.
But if I had gained weight over night, I would know in my brain that I was experiencing pain all at once and wouldn't want that.
George Clooney has always been reasonably fit. But he had a role for a movie a few years back where he had to put on 30+ pounds. He described in many interviews how that extra weight caused him lots of pain and he didn't want to do that ever again. I think of him as the frog being put in the pot of boiling water.
Now when it comes to those of us who have gained all the weight back after having lost it successfully on Atkins, I think the problem lies in the weight slowly creeping back on with cheating here and there, getting discouraged, not making time for working out, and feeling discomfort in our body but putting up with it. And then you look in the mirror and say, "Oh my gosh, what happened, I put on 50lbs!"
If we experienced the pain of being over weight all at once, we might not want to go there ever again.
Hope this makes sense.
And for me, I haven't been at my ideal weight for over a decade or two.
I have no idea the extent of pain I really am experiencing right now that would be alleviated by the weight loss. But I'm willing to find out.