@GlinnerForPM
If you get an hour for lunch you should use it to eat. On the other hand, do colleagues who smoke use their full lunch hour plus extra time for smoking?
This has come up in our office but it was ultimately decided there's too many variables to have hard and fast rules. I have a cigarette in the morning and one in the afternoon. I make one coffee for myself, usually before I actually start work. Others in the office have a coffee hourly, so the equivalent time I spend smoking is stood standing by the kettle, for them.
Another colleague smokes hourly but always comes in 30 minutes early to make a start on overnight admin. Other people may need to take short personal phone calls regularly if they have kids, someone they care for or ongoing medical treatment or legal issues etc. Without exception we all work more than contracted as and when required. It's all swings and roundabouts and averages out. There's an understanding and trust that we don't take the piss, but that probably only works because we're a small friendly team.
I agree with the OP above, there's no point being snidey about other people having a whole hour when for many roles that is what is contracted and not being able to take that amount of time is a deeper issue.