There was a very interesting interview on Norman Swans' Health Report on ABC Radio National last week. Here's a link to the transcript:
Radio National Transcript: The effect of weight loss on hormones
Basically, a recent scientific study shows that people who are fat for a long time may see changes in the level of hormones involved in making them feel hungry. Even after a year the hormone levels stay at the abnormal levels, increasing the chance of weight-gain after weight-loss.
It's another reminder that weight-loss is the easy part, but keeping it off, especially for a person who has been obese much of their life, may be a much harder struggle.
For myself, I believe that when I eventually go into maintenance mode this will reinforce constant vigilance. A good thing, perhaps?