I alway knew what a portion size was I just happened to choose to eat 3-5 portions of everything per meal. For me the Biggest Keyto Re Learning to eat was SLOWING DOWN and CHEWING every mouthful before I put more food in my mouth. It now takes me approximatly 1/2 hour to eat 4 ounces of Fish, 1/2 a Sweet Potato a portion of Vegetables and a Salad. In the past I would have demolished that in 3-5 minutes tops and I would have been looking for more food.