Jeeeesus, I remember a few years back when we were exactly the same weight and you were talking about trying to get down to 70kg. And now there's 12kg difference between us!
I think this will be a bit of blip - I have managed to put on 2.5kg quite easily in the last week so my body doesn't like being too skinny.
Who would have thought that there would be such a difference between 10 weeks of hard core marathon training v poker playing.