I think most people generally have breakfast, lunch and dinner. I did growing up. My kids did growing up. We didn’t “graze” in between meals because, as mom said, “It will ruin your appetite.” And this is true. She wanted us to actually be hungry when the dinner she’d worked on for an hour or so was ready. And we were!
This eating 3 times a day really is a social construct. It’s based roughly on a farmer’s work schedule. As an adult, I only eat twice a day, breakfast and “dinner,” which is usually around 3:00. I don’t eat again after that.
I don’t eat when I’m not hungry, and when I do get hungry I usually wait a couple of hours before I eat. Hell, on Sundays I may not eat at all until “dinnertime” at 3:00. Here at work I will snack on sunflower seeds at “lunch” time. It’s kind of a stress reliever thing. Breaks the tedium of just sitting at my desk.
The problem with it is it does increase the quantity of food that we eat. We’re used to having X-amount of food at breakfast, and at lunch, and at dinner. When we rather mindlessly snack (like me and my sunflower seeds,) we still eat the same X-amount at our regular meals.
As @Zenvelo said, he worked with a woman who started bringing lunchables to work for lunch. After a month or so she began to eat it on her coffee break and going back out at lunch for a sandwich.
Snacks just weren’t a thing for me growing up, and it wasn’t for my kids either. I just wonder if they have a culture of “snacks” in between meals in other countries.