The members of my team always go "for lunch" all together and invariably always to the same shop nearby, just to grab the cheap sandwich and then eat in the office. I would strongly prefer to eat more normal food, there are completely affordable public canteens nearby, slightly more expensive (not even twice). Is it possible to disengage from the team without creating tensions of the kind "he does not like us"? What is the best, most professional phrase to say I am going on my own?
just to grab the cheap sandwich and then eat in the office
"Thanks team, I think I'm going to eat _____ instead. I'll meet you back in the cafeteria/break room/etc."
There's no obligation to eat the same food as them, and since they bring it back to the office anyways, you can still be a part of the group (if you desire).
One option is to find another takeout place and meet with the rest of the team after each gets their own takeout. You would still eat with the team.
Or if you want to go someplace else, that's fine too, as long as you make sure that you seperating from the team is simply because of the food choice and everybody understands that.
Just be proactive and ask the others to join you.
Hey guys, I heard there is a nice place just around the corner, it's called X. I'd really like to try it out, you want to join me? I though about lunch today, but we can make it tomorrow or even friday if that's better.
Now the ball is in their court. Maybe they don't like the place, maybe they don't want to change their routine, but that's on them. You certainly tried.
If the team is large enough, they might even split up depending on personal choices. We always had the daily menus of the canteens around us and would decide based on what people wanted to eat. If someone really craves asian food today, I'm not going to hold that against them. Next day it might be a burger we both want and the day after maybe I'm in a hurry and just have a sandwich and they go get a lasagna. There is no need to spent the lunch break together, it only gets akward if it's not about food choices.