Help needed with a 5 year old

My son is 5 in Feb and he is constantly hungry can any mor eexperianced parents help me here is this naturalor just greed?.

He has ceral for breakfast then usually a snack afterwards he has a fairly decent lunch and a good dinner but he just seems to always be hungry he is not fat at all.

Is this just a phase or does it happen to all kids?, and will it ever stop?.