I have been known to get like this but it does not happen too often. I usually find it can happen a few times a month where no matter what I eat, I never seem to be full and it leads to me snacking.
When I get like this and have the munchie, crisps (potato chips) are something I love to eat.
I'm always hungry! I try to not think about it, but what's really difficult is having a house with open concept. The kitchen is right there, so it's too convenient to go grab something to eat.