- Read your contract - if you are not paid for lunch, then don't work during it. Forcing unpaid labour is generally a crime.
- Learn your labour laws (sometimes "Employment standards"). At both the federal and provincial / state level.
- Physically shadow your boss or manager during her lunch break. Most managers won't make a complaint against you when you take the same lunch break as they do.
- In a larger employer, contact your HR staff for workplace well-being or work-life balance information and guidelines.
If possible, consider a government (including civilian for the military) or unionized job, when you better protections (namely more means of recourse in the event of unfair disciplinary action) of your legal rights.
Better employers will recognize that healthy employees are more productive employees (i.e. better ROI), and often accommodate both a real lunch break, and when possible, routine physical exercise, some even provide gym facilities or discounted / reimbursement for external gym memberships.
Try to work on team projects, these generally involves more interpersonal interaction which can turn into physical meetings (when appropriate). Boxing or sparring is generally not a positive team environment, even if it is very physically satisfying. Make use of compile time.
In a help-desk type role, in-person service delivery or follow-up contact (i.e. best after a solution is found) can have a huge positive impression on the quality and professionalism of your work. This of course is not always applicable, but when you can make it fit, try it.
What are some IT jobs where you don’t sit at a desk for 8-10hrs a day?
Corporate spy. Or corporate physical security pen-tester if you want to get technical.