Can I come and work for you, @GucciDahling? It's amazing you are investing so much into your staff's health and wellbeing!
Have you thought about providing the option of a standing workstation? Sitting all day long is killing us, and I am starting to see standing workstations more and more often.
Also, I don't know if it is do-able, but teaming up with a local sports shop and providing some incentive for your staff to invest in exercise gear. I know once I bought my lycras and proper shoes I was much more keen about exercise than just wearing my daggy old trakky daks