I lost 10lbs in the last six weeks of writing up (no time to eat!) - mind you, I was quite pleased about it! Apart from that my sight is not as good as it was, had perfect vision pre-PhD now decidely dodgy. I have decided that this is 100% due to staring at computer screens and nothing to do with getting older! You are right, PhDs may be good for the mind but I don't think the rest of the body gets much benefit!