For about ten years my kids did not eat dairy. There were good health-related reasons for this at the time, but it was never easy. Restaurant kids' meals are full of mac'n'cheese, pizza, cheeseburgers. Birthday parties are much of the same (incidentally, I used this as an excuse to avoid Chuck E. Cheese entirely. That was bonus.) If it wasn't hard enough to live in Tex-Mex central, I'm from Wisconsin. Every time I'd buy soy cheese on vacation up there, I worried that my name would be put on a list...
About a year ago the kids decided they were done with that particular austerity. They made some experiments and when things seemed to be OK, they dove back in wholeheartedly.
Pizza! Bagels with shmear! Ice cream! Cheeseburgers! And holy cow, the quesadillas. Their latest birthday party featured cheesy bean dip, a 28" pizza, and an ice cream cake. Their lactose-intolerant father was most envious.
Keeping the fridge stocked when you have teenagers in the house is always a challenge, but I've had to resort to rationing or we'd be at the grocery store EVERY day. A carton of ice cream every two weeks. ONE pack of tortillas, not all the tortillas in the world. Balanced with pretty much as much fruit and veg as they want.
Our next big milestone is Coming of Age. What are we taking to the brunch? Bacon/panko-crusted macaroni and cheese and a baked brie.