I know a recruiter who years ago bought a drafting table for his work desk. He believed that standing at his desk was healthier than sitting all day.
Today he is the same weight as when he bought his drafting table. Of course he also tries to maintain a healthy diet and exercise program. The connection with standing at this desk does seem to have a connection with his weight maintenance.
Some of us have desk job and such is life. We work where we work. What I have begun to do is return to a practice I had a few years ago, which was to walk in the morning, walk to a mall nearby for short breaks, walk a half hour at lunch, and take a walk in the evening. On days when I have yard work, I count the yard work against the requirement to walk. All of these walks add up to an hour and a half a day of being on my feet. I am not spending nearly as much time on my feet as my grandfather, who in his seventies would spend on his feet working on his farm.
The change of pace with the walks added to my schedule makes me more focused and efficient at work and will hopefully increase my health future as well.