Sitting all day is bad for you!
1) Minimal calorie burn
2) Places the muscles, tendons, ligaments, etc in a habitual state that the body adapts to. The question is: Are you ok with your body being optimized to sit?
3) If you are optimized to sit, that means other movements suffer.
4) Even if you are a regular exerciser, there are plenty of studies that show the negative effects of sitting all day can not be offset.
5) Our ancestors were not habitual sitters, we are only beginning to understand how the new possibility of being able to sit all day hurts our health.
What to do:
1) Don't sit all day.
2) Take regular chances to get up, walk around, or even do something strenuous.
3) Look into sit/stand type of desk setups
4) Treadmill desk
Now I am going to plug my own incredible "Beat the Seat" program. And it is yours for free!
Setup your workspace so that you have the option of working in a seated or standing position. If you have done research into options for this, you might notice that they can be expensive. I have a ghetto setup: I basically utilize various boxes and shelves in my cubicle, price is free! The program is simple: Half an hour sitting alternating with half an hour standing with five pushups in-between transitions. I have been doing it for a year and a half now and I notice a difference. Try it!