Hunger hungry.

Are brain processes everything that happens to us all the time. One thing that it process is the feeling of hunger. What causes us to suddenly get hungry? Why can we get hungry, not eat but then not feel hungry anymore. Or like what happens to me. I was at the dorm and there was no food to eat today. It was fine and after I looked around and saw there wasn't much to eat I wasn't that hungry . However after I came to the Perls house and the fantastic, amazing and nice Mrs Perl offered me food, I suddenly got super hungry. That got me thinking that are brain is really a big part of how hungry we are.
Are thalamus is what detect when we are hungry. It is also what causes us to do actions with out thinking about why we are doing it. Like reflexes and controlling are body temperature. Therefore when someone is says something about it we involuntarily get hungry.
Hearing about having food causes you to get  hungry the same way as when you see a picture of food. It can be that we saw a picture of food and didn't even notice that we did but suddenly we got hungry. It like subliminal stimulation and priming. We are not conscious of the fact that we saw a picture of food but we suddenly get hungry.
When I am somewhere and there is no food  I am not going to get hungry because by brain knows that there is no food to eat. Nothing is causing my brain to go oh I want some food. Unless I am actually starving. However when someone offers me food my body unconsciously causes my brain to go oh ye I actually didn't eat I am hungry. Then I get happy when I eat food. :) It crazy how much are brain effects every aspect of us. super cool though! Just like Mrs Perl giving me food!