[undersuit]

Abstinence is a form of penance. Frankly if the office doesn't bend over backwards for your self-flagellation every week I'm OK with it. Are you demanding that the entire office fast with you if they can't find a pescatarian option?

[throwaway_l33t]

You missed the point: if I’m planning lunch with my friends and they want to go to barbecue on Friday, I’m going to be suggesting an alternative so I can get something to eat too. Just like we had to plan lunches around my Jain, Jewish and Muslim coworkers dietary restrictions.

So, in fact, some people will have to do something different to include me in some of their activities.

[undersuit]

Just go to confession afterwards, it's not a carnal sin, and it would remove your self-imposed inconvenience on your coworkers.