I could probably be included in the list of people who eat the same thing every day (at least for breakfast and lunch), and from what I've seen, it seems many of my coworkers are the same.
As for why? Well personally, it's probably a mix of the following:
1. It's easy to not have to worry about what you're going to eat and what it'll taste like.
2. Choices of places to eat are limited in many areas. This isn't so much the case now, but it certainly was for some roles in the past, where the office was pretty much nowhere near a major shopping area/main street.
In that case, it was 'eat the one thing you find palatable in the canteen or get a train/bus/drive/cycle to a place with shops'.
3. My personal tastes are very plain and somewhat picky, to the point of disliking pretty much anything with extra sauce, relish, mayonnaise, spices, etc.
Either way, all of these things are likely reasons for many others too. Many people on the autistic spectrum for instance are rather picky in terms of favoured foods, and will generally stick to the same meals as much as possible. Many people are based in locations where choice is limited/a hassle in general.
And there are other reasons too:
1. Some people like having a routine (as mentioned in other comments)
2. Some like to know exactly how healthy their diet is, which is easier with a limited choice (also mentioned in other comments)
3. Quite a few people probably prefer eating at their desk while browsing Hacker News/Reddit/YouTube/the internet in general, which precludes going far for shopping.
4. If you're a workaholic, it's easier to stick with one type of meal rather than having to prepare different ones/go shopping.
As for why? Well personally, it's probably a mix of the following:
1. It's easy to not have to worry about what you're going to eat and what it'll taste like.
2. Choices of places to eat are limited in many areas. This isn't so much the case now, but it certainly was for some roles in the past, where the office was pretty much nowhere near a major shopping area/main street.
In that case, it was 'eat the one thing you find palatable in the canteen or get a train/bus/drive/cycle to a place with shops'.
3. My personal tastes are very plain and somewhat picky, to the point of disliking pretty much anything with extra sauce, relish, mayonnaise, spices, etc.
Either way, all of these things are likely reasons for many others too. Many people on the autistic spectrum for instance are rather picky in terms of favoured foods, and will generally stick to the same meals as much as possible. Many people are based in locations where choice is limited/a hassle in general.
And there are other reasons too:
1. Some people like having a routine (as mentioned in other comments) 2. Some like to know exactly how healthy their diet is, which is easier with a limited choice (also mentioned in other comments) 3. Quite a few people probably prefer eating at their desk while browsing Hacker News/Reddit/YouTube/the internet in general, which precludes going far for shopping. 4. If you're a workaholic, it's easier to stick with one type of meal rather than having to prepare different ones/go shopping.
There are many reasons really.