"What you eat" is definitely a huge part of it. For me, when I'm on plan, I don't eat much. For quite a while, until I upped my exercise, I was sated on 800 to 1000 calories a day, as long as it was all under 25g carbs and not processed.

My satiety cues are nonexistent when there is junk around though. While I can be very happy on a piece of chicken and some asparagus, put an extra large pizza in front of me and I will eat it all.