What food category does a protein shake fit in?

I have to analyze a classmates food intake and compare it to the food pyramid and they have protein shakes down. Does that fit into the food pyramid at all? As what?|||Don't put it in w/ meat like the other guy said. Chances are it's whey protein which is DAIRY and if it's mixed w. milk that's obviously DAIRY too.|||Put it with the meats because they both have a lot of protein.