If you're hungry, it means you need to eat, probably because you're growing. You may get a little round at points, and still feel hungry all the time, but usually you grow right afterwards and thin back out. Man, when I was 6-11, I ate constantly, I was always ordering more than my friends when they'd be over for a play-date and my parents would take us to get fast food for lunch. But when I was done growing at about 13 it was like my stomach shrank to a third it's former size, and I just wasn't hungry anymore. Just watch out for frequently eating when you're not hungry, or eating past the point where you feel full, those aren't good things to do. Your body should take care of the rest.