I tried to save money once by making lunch and bringing it to work. My SO at the time who was much more frugal than me pointed out that eating lunch out (socializing) was much more important to them than the savings which over the course of a month was not that much, especially if you factor in the cost of time and that there were way more effective ways of saving money than giving up socializing time.
It was also boring (for me) in that in order to save time and money I'd end up having to make a larger portion of one thing and then eat the same thing all week.
In many cities in the us eating out is as cheap as cooking. I'm not 100% certain but someone told me it's because you have to consider economies of scale for an eatery and real estate prices and commodity level revenue streams for the supermarket.
Provided the workers scoop deep, a chipotle bowl is generally two meals for me, especially if I get a tortilla on the side to build a burrito with the remnants later. Lunch and dinner for ~$7, breakfast can be a cliff bar for another buck. So ~$56 a week to eat out every day, not too bad if a $50 weekly grocery bill is the rule of thumb.
You barely get two dinners for $50 here in Sweden unless you go for fast food which isn't an option if you're going to be eating out every day. A typical lunch is at least $10.
If I'd eat out every day both lunch and dinner I'm going to pay roughly $800/month compared to my usual $300/month for groceries.
It was also boring (for me) in that in order to save time and money I'd end up having to make a larger portion of one thing and then eat the same thing all week.