I decided to give it an 8 week trial to see how I felt about it. I'm nearly halfway through and I am very happy with the direction things are taking. I really haven't even lost much weight - a little over a pound - but I've lost 3 inches from around my belly. My eyes are clearer, I'm more focused and calmer. My family has commented on the fact that I'm able to get through the stressful routines of family life more serenely than before.
I have weight to lose. A lot of it. But if that is the main motivator behind doing the 5:2, the Crazy Diet Lady that lives in my head will take over. No good can come of that. So on non-fast days, I'm not really denying myself anything. Any changes I make may be to add more vegetables or exercise. I do hope my weight comes down, but for me it's got to be just a side benefit of the lifestyle.
Thanks for all the information in these forums!