Regular exercise/activity probably keeps me hungrier than anything else. But I've also just learned to just to eat when it is mealtime even when I don't have much appetite, not that this is too frequent. My dad was a 'clean your plate' kind of guy so that is now in my programming, especially when someone else cooks the meal. Eating on the clock is easier to do if you find a way to make it social like regular family mealtimes, a specified lunch break with coworkers, or a scheduled breakfast with friends. Or if you have tons of discipline, set the clock and make sure you have a take in some minimum of easy to prepare and palette calories when the alarm goes off. This is were the shakes and energy bars come in handy.
One of the worse things for my appetite is to just pick at foods here and there. If I'm grazing nonchalantly throughout the day, especially on carb rich snacks, I never really get motivated to face down a substantial meal. So I end up missing out on the proteins, fats, and other nutrient dense foods I need.