I've been doing the 5:2 diet now for around three months now, and just this week my min weight hit 90.0kg! As you can see from above there is a lot of volatility in my measurements; I measure myself every weekday at around the same time, but there is still easily a range of 2kg in the measurements. My fast days are Monday and Thursday, and my weight, unsurprisingly, is lowest after those days.
If you look at the data since my records began, you see the effect on the weekly average:
It'll still be a while before I average below 90kg, but it's encouraging to see it going down.
Overall, the fasting days are a lot easier to do than I'd thought. You have 600 calories to spend, and I usually split these between 300 calories for coffee/lattes in the morning and during the day, followed by 300 calories for a meal in the evening. I don't have much variety in meals; typically it's some pitta bread with sliced meat. When I do vary, I stick to what I can easily scan into http://www.myfitnesspal.com/
I chose Mondays and Thursdays as fast days because I don't do much in the evenings on those days, which makes it easier to stick to. I've found I can do exercise on these days too; I'm up to 6 mile runs with no obvious ill-effect.
On off-days I've been taking advantage of "eat what you like" a little too much. The freedom is nice, but to be honest, I do sometimes binge. I don't think this will ultimately effect whether I will reach my goal, just when. I've done around 3kg in 3months, and being down to 87kg by June would be nice, but 85kg would be even nicer!