Fruit never makes me feel full
I know there's food in my stomach cause the bowl is empty. It's just not mentally satisfying I guess.
You have to make the distinction between actual physical hunger (stomach growling and it's been 3 hours or more since you ate) and a craving (oh, I just remebered there's a bag of chips in the cabinet--I must go eat them).
If you're not eating enough at one time, then you may get hungry sooner than you should. Figure out how many calories you should eat per day and divide that up between 3 meals per day and some snacks. Like photochick said, you need to journal and figure out what you're eating, when and why. Then you can go from there. I personally do not like tracking online. I prefer a small notebook and a book of calorie counts.
If you're constantly obsessing about food, you're probably not eating enough.