The process of eating a small meal before you eat in order to work your way into a larger meal. This process is beneficial to prevent an upset stomach when one is extremely hungry, or to ensure that one does not spend too much buying a larger meal in order to satiate hunger. This process is not to be confused with snacking; pre-eating deals more with meals in smaller portions like appetizers or small microwavable meals.
I didn't eat anything ALL DAY! I need to pre-eat before we go to that buffet or I'll get myself sick.
John: Aww mann I'm still hungry. That cheeseburger didn't work.
Craig: Shoulda pre-ate.
I've been pre-eating for Thanksgiving all day. BRING IT ON!!