A lot of people seem also to eat for the sake of stimulation, rather than just because they're hungry. If you have a high metabolism, you can get away with that sometimes, but if not, you need to learn to adjust your desire to eat to correspond with your body's actual needs.
This also applies to what you eat. Proteins and fats will give you longer lasting energy, so those will make for better snacks than carbs and sugar.
I think most people would find a lot of benefit by getting rid of high-carb and high sugar snack foods from their pantry and waiting until they're hungry to go looking for food.
Coffee or tea is a decent way to have something to sip on if you just want stimulation.