For dinner we usually have steak, pork or chicken of some sort. Vegetables and some kind of rice, pasta etc...
On lazy nights I'll order a pizza. Sometimes just throwing some chicken strips and fries in the oven will do the trick.
As for breakfast, I usually will eat a quick bowel of cereal at work or a donut and coffee in a pinch. Lunch at work usually entails leftovers from home or I'll hit up a deli or something for a cold cut.
America's traditional meal setup is a light breakfast, medium lunch, and large dinner. It's not the best idea, but it's just traditional. You probably come from a place where you eat 4-5 small meals throughout the day so I'd imagine it's strange.