Add in the first aid stuff that I usually carry, knife, lunch, phone, mp3 player, papers and a gym bag and you have quite a bit
of weight day in and day out.
Do you not have a rape alarm whistle hanging from your neck, as well?
(Actually I knew a Professor of Philosophy, bachelor, who had one. Never went anywhere without it. Probably a way of reassuring himself that he was attractive enough to warrant it. But he wasn't).