I'm currently on the 5:2 and just starting week 3. The second fast day was a bit of a wash out as I ended up going out in the evening, but after the first 4 (3.5!) fast days I'd lost 3lbs. I have just over another stone to lose. Feeling very optimistic about this as have done WW before and just got bored with counting points after a while. I think this should be a lot more sustainable. DH has started today as well so this should help too.
I'm having a go - but not the Michael Mosley one, another one by Dr Michelle Harvie and Prof Tony Howell. A relative is a dietician and said that the more famous one didn't work so well for women, and that this one (called the 2 day diet) was more scientifically worked out.
I have only read 4 chapters - so I can't comment any more than that!
I'm on week 2, done one fasting day today (difficult) with another planned for tomorrow. No change seen yet in weight / body fat etc.
I'm on it and have lost 1.5stones, fasting on 2 days per week. I lost the first stone doing 3 days per week fasting and have slowed down now and am maintaining the loss on 2 days, tho' I'm not religious about it and don't turn down a nice meal out if it happens to be a fast day.