I have learned many times that when you are single or a couple, there is not much difference in cost between eating out every night or staying in and making your own meals.
Eating out is expensive, especially for families. For single people and couples, however, it is sometimes the lesser of two evils.
The problem is, for single people and couples, buying bulk does not provide a great advantage to leverage savings. There is not much point (or freezer room) to buy a 4-pound bag of frozen broccoli, for example, when there are only two people eating it. They will likely not eat it in a reasonable amount of time (before the broccoli suffers freezer burn) and they would not go through it fast enough to keep from running out of room in the freezer or refrigerator if they always bought the family size or bulk items.
What happens instead is couples buy enough for two. Even in doing so, in my experience, Nicole and I end up throwing out a lot of fresh food if we do not get through it in time. It can be frustrating to watch the food you paid for go in the trash, untouched, still in its package. Fresh spinach, for example, only stays fresh a week or so if we are careful to buy the furthest out expiration date. Because we live busy lives, we might plan to use it in 2 or 3 dishes, but end up only using a handful of it once due to Nicole or I running too late to cook a full meal that night. If we do not eat it, there are no kids or transient guests who might, which would at least make it seem like it did not go to waste.
Instead, we end up paying top dollar for smaller amounts of groceries and still eat out a couple of times of week due to unplanned scheduling hiccups, or personal energy that day (too tired to cook), or plain convenience (we could spend 2 hours prepping, cooking, and cleaning, or just head over to Stella’s for amazing nachos).
I do not mind paying for good local food prepared well by ethically run, vegan-friendly restaurants. A decent meal at one of our favorite local spots might cost $30-$40 for both of us and often there is enough food to have leftovers for lunch or dinner the next day, making the actual cost $15-$20 for two meals for two people. Not bad and not far off from what we would spend on groceries over the same period.
The other nice thing about eating out is the diversity of food offered. When we buy groceries and prepare meals at home, they will basically be variations on the same 10 or so ingredients for the week. Visiting our local restaurants, though, exposes us to ingredients we do not normally come across and a wide range of dishes we have neither the time nor the inclination to make (but love to eat!).
I am not defending restaurant-eating as a lifestyle. It has problems, too. The food is usually of poorer quality than what we would make at home. It is produced in large quantities (which can mean lower quality), often loaded with sodium or just over-salted to make up for lack of flavor, and even the cleanest restaurant is a breeding ground for vermin and other unwelcome food visitors.
Still, when you are single or there is only 2 of you, family style-cooking is not always the best way to go and you are unlikely to prepare yourself a five-course meal.
Use eating out as a strategy for when it makes sense. When the trade-off is worth the expense and convenience, enjoy a night out, but also avoid the big-box restaurants that are not offering a diverse menu of local goodies and food you would not otherwise make at home.