A quick post here just to get it out there, and I'm already a couple weeks behind the curve. Oddly haven't heard too much about this, or perhaps it's because I've lost the will to deal with the community that would jump on this? Who knows :-)
There is a new NIH funded study out of Columbia (Rosenbaum & Leibel) published this month: Models of Energy Homeostasis in Response to Maintenance of Reduced Body Weight
I'm going to limit this post to just one of the three experiments conducted:
In 17 subjects (14 women, 3 men) weight stable energy expenditure and body composition was determined following a period of 6-8 weeks of weight stability. They were then put on an 800 cal/day diet until they had reduced their weight by 10% of initial weight. This took 7-13 weeks, after which their food intake was increased to achieve weight stability at the 10% reduced weight for 6-8 weeks. Energy expenditure and body composition were measured here. This was repeated to achieve 20% loss, where the second weight loss phase took 8-14 weeks.