Oh! OK... strap yourself in 
I lost 3 stone over 2 years, 5:2 ing as and when I could. CFS makes it a bit difficult. Stress and leaving teaching means I have re-gained 1 stone in 2 years - not too bad I suppose. So I am looking back at my MFP diary to see how I did it!
I do Johnsons Up Day Down Day Diet - I started before Michael Mosely's programme and the renaming, so I use Up Days Medium Days and Down Days
Up Days I never really set out to do anything. Just eat whatever my DD made me want... but I found that I started avoiding sweet things and starchy carbs without really thinking about it. That took about 2 or 3 months to kick in. MFP tells me that my mid week UDs I ate about 1500kcals, more at the weekend, when we chose to make more complicated meals, drink wine, have pudding etc. Though Sunday lunch and pudding never really hit huge numbers.
DDs I started at 800kcals. Suffered the headaches for about 2 weeks and suddenly, after about 2 months, felt different. Took me ages to realise I had grown a Full Button... I got down to about 300kcals a day, the occasional full fasting day. Days stretched to about 40 hours every now and then.
MDs were either U or D Days that went wrong. I didn't get angry/disappointed, I just relabelled the day and carried on with whatever the next day was.
After 6 months it felt great. I was never hungry, ate whatever I wanted within the calorie limits I set for the DDs. I never restricted UDs but found that I naturally started to eat very healthily. I continued to bake cakes, make puddings, eat a wide and varied range of foods. The only thing I did was eat 500kcal a day, twice a week, three times if DH was working away.
Mon; Weds = DD
Fri = DD or MD if he was home
Tues; Thurs; Sat; Sun = UDs
Exercise was done on the morning of an UD, before breakfast if I could manage it. I have a sport/exercise science degree so did a lot of reading in the local Uni library on this... the original 5:2 authors recommendations are very sensible and give good results.
I was almost at Maintenance - 1 DD per week - when I lost the plot, got very stressed and, eventually, left teaching. I wasn't in any fit state to continue, but, as I said, it has taken 2 years to put on 1 stone, so I didn't lose all of the habits immediately.
The great motivators were losing all my back fat in within a couple of months - that made an enormous difference to my posture and the clothes I wore
My knees stopped complaining. That meant I could do the exercises my CFS restricted me to, so I was more active, safely.
My face, chins, all got smaller, my boobs didn't 
but the loss of back fat meant I looked much, much better.
But I know a few people who never got into it. For them the headaches were monstrous and they loath the diet as much as I loved it. Happily you will know within the first week if this will be you. I think everyone gets headaches initially, I did and expect to again, but if they are too bad, just stop and choose another diet.
The DDs mean that you end up reducing your kcal intake so that over a week you lose 1 -2 lbs (though it can be far faster initially). So, regardless of the Monster Shouters, you aren't starving yourself, there is no Starvation Mode, and the average weight loss is very sustainable and falls within the NHS safe limits.
The reason I chose it was I can't be bothered counting calories, eating special foods. So I chose 3 or 4