In reply to tlm: Interesting , that's what I was thinking.
What is really weird is that a few years or so back I was always between 13.5 st and sometime almost 14 (really felt quite chubby then).
I lost about two stone in 2005 when I ran a marathon, and have essentially kept it off since then.
Although I eat all the wrong things (and drink way too much ale) I am very active (for an old git) and I think that this is the only thing keeping me from planet chubb.
Part of me thinks that if I'm just a bit careful with what I eat (and drink) I could be lean - rather than having a smallish muffin.
I did put a stone in weight into a small backpack and can't imagine how much harder trying some of the sustained roof boulder problems would be.
Also since bouldering I am alot less scared of running out of juice on strenuous moves, and maybe think that further weight loss might take that further.