Not true for the Swiss, it is quite common for people to bring a lunch, only for the offices in central districs is it more common to go somewhere else to eat.
My experience of Swiss is really limited and "in central district" but... The first time I bring my meal I was told like a father to a child "no, here you work, there you eat, we are humans not slave nor machine" and it wasn't a "left-wing extremist"...
Yes, you won't eat at your desk, usually a few people will go to a kitchen area or meeting room and eat together. It definitely isn't the American style of eat-while-you-work.
