When you are hungry your hypothalamus releases a chemical into your brain called NPY which basically makes you feel unsatisfied or hungry... Say like you eat a slice of pizza the nutrients in their should fill you up yet it doesnt and 10 minutes later your going back for more that is because of NPY.. on the flip side of that if you eat a well balanced meal in complex carbs and lean protein with adequate calories your hypothalamus will release another chemical called leptin which makes your feel full and satisfied.
Ways to tweak it so your mind is satisfied as well as your body are drinking water when you are hungry as this will help you release leptin... eating peanuts or almonds(unsalted) before a meal so you already feel satisfied before you start to eat whatever nasty meal your eating... and last but not least make sure all your meals have decent dietary fiber... 30-50g a day is what it takes... this will slow down the food going through your intestine to make your hypothalamus produce leptin and keep you satisfied.
I learned that from the YOU on a diet book!