I'm adding my experience to this as I found this thread (and the main thread - on which I've only ever lurked) really helpful at the start of my 5:2 journey.
I've always considered myself naturally petite. Pre DC I was quite sporty, and could eat what I liked. My 'natural' weight hovered around 8 stone.
I've had 3 children. With each I gained quite a lot of weight, and after DCs1 & 2 I lost most, but not all, of it. Each time I got pregnant I weighed a little more than the last time. I've tried a few different diets - WeightWatchers, Cambridge, just eating healthily - and although they worked, I also found them really soul destroying, so only stuck with them for long enough to get my BMI into the 'normal'' range, then accepted that as as good as it was going to get, and gave up.
I was pretty upset, in February of this year, to step on the scales and weigh in at 11 stone. I'm short, and looked really heavy at that weight. With a baby and 2 young children I don't have much time to exercise, and I couldn't face starting down the WeighWatchers type of route again, preparing separate meals for me and the rest of the family.
So I decided to try 5:2, having watched the Horizon programme a few years ago, and having known a few people who had tried the diet.
It's been brilliant. A little more than 4 months later, and I now weight 8 stone 13. That's less than I was originally aiming for, but I find the diet so easy that I'm now going to keep going and try to get to my pre-DC weight.
Fast days were initially hard (I'm breastfeeding so have additional calories to take account of this, but it took a couple of weeks to work out a pattern of eating and amount on fast days that worked for me). But now I hardly know that I'm doing one. I love that I can eat with the family for most of the week, that we can still occasionally go out for coffee and cake, that the children haven't even noticed that I'm dieting.
I'm happier with my weight than I have been in 5 years. I'm just so glad that I found the 5:2 diet 
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