As both children and adults, we have brains that are usually very good at telling us when we are hungry and when we are full. You may notice that, just before dinner time, you start feeling hungry, even if you are busy playing an interesting game. But you do not usually feel hungry all day. This is because we have a hormone called "ghrelin." that increases in the blood just before mealtimes or when we have not eaten for a while.
Ghrelin comes from the stomach and travels in the blood. Ghrelin ends up in the brain and tells the brain to feel hungry and start eating. Just like the players on a football team, all of the different parts of the brain have different jobs to do. They keep communicating with each other to help each other out, but they still have fairly separate functions. The part of the brain that ghrelin talks with to tell our bodies that we are hungry is called the hypothalamus. The hypothalamus is really important.

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