One thing I would like to mention which I don't think has been covered before in this thread ...
I have lost a lot of weight in the past, often pretty quickly, at say 2-4 pounds a week. I experienced an odd sensation each time of my body being the wrong size! It was as though my mind had not managed to make sense of what was happening.
This time, I have done it much more slowly, averaging about 0.75 pounds a week, and it just feels 'right'. A consequence of this is that I feel that I will keep the weight off this time. I feel as though the smaller body is one that I own permanently, rather one that I have borrowed from somebody else!
I am sure that this effect is another explanation for why crash diets never succeed long-term.