I came across this article and found it really interesting. It seems to have some pretty strong evidence for what I've always suspected. Someone who loses 50lbs to get to 150, for example, will have to consume less calories to maintain than someone who has a similar weight without any weight loss effort.
I also found it interesting that the "hunger hormone" is about 20% more abundant in people who have lost a significant amount of weight, which also explains why maintenance can be so difficult.
I think this just reaffirms the idea that weight loss truly is a lifestyle change. One can't just lose weight then go back to "normal" after and expect to keep it off.
I can't actually post the link to this article because my post count isn't high enough. But if you go to the Google homepage and search 'New York Times the Fat Trap' it will be the first result.