Yes, Matthew it is amazing. All of our children have different appetites and eating styles. They all have different body types also. When our oldest, who is 19, was 3, he would eat so much I thought he might get sick. One evening we had eggplant parmesan and the child ate 3 servings!
Our #4 son is 5. He is always first to come to the dinner table and always the last to leave. He's a big rice eater. He likes steak too.
Our soon-to-be 3 year old daughter loves veggies and if you don't quickly serve yourself, she will help herself to the entire bowl of whatever veggie we have, especially broccoli.
Our oldest daughter, who is 7, used to eat huge amounts of food, but now, not so much. She also is averse to milk and butter, but she likes cheese.
Meal time can be quite confusing, as we have some who don't like to eat meat, some who don't like legumes, some who don't like green vegetables, some who don't like dairy...Ugh.
But yes it is truly amazing how much children will eat.
In my experience, don't worry too much about them becoming overweight or nutritionally deficient. When our #3 son was 5, he would only eat hot dogs or wheaties. That was it. When I took him to the Dr. for a check-up the Dr. (who was really old school) laughed it off. We had never experienced this before, and he assured me it would pass with no adverse effects. It was true.