Eat whole foods that aren't processed...
hard boiled eggs, apples, bananas, oranges, nuts, etc.
breads, cakes, chips, ceral bars, nut bars, energy bars and anything else processed (even if it claims to be healthy) will not fill you up.
If I'm really hungry in the middle of the day, I eat a banana or apple and a hard boiled egg.
The combination of protein, carbs and fat helps you to stay full feeling. The more processed the less your body recognizes as food and doesn't feel full. The more sugar overhauls, same thing. Sugar rush, crash, want sugar again, repeat cycle.
Sure, sometimes doritos do come into the picture, but I don't buy them normally.
I hope this helps...its just the truth. I am a size 3 and I eat all the time...I just make sure it's good food...not processed crap.
People will forget what you said, they will forget what you did, but they will never forget how you made them feel.