“Full” is an ambiguous term. My experience was that for the first few weeks, I ate the same quantity of food as I had been eating on my high-carb diet. Then, one day at lunch, I was halfway through the meal, and wham! I was done. I had to put the rest of my plate into the fridge for later.
Looking back, it seems that my body actually needed the larger quantity of food for the first few weeks, but then it adapted to the new way of eating, and apparently my insulin dropped to a level that stopped interfering with my appetite hormones.
That lunch was my first experience of satiety in many, many years, if ever. The difference for me is that “full” means a stomach stuffed literally to the point where any more food might cause a rupture, whereas “enough” means I am no longer hungry. As a carb-burner, I could be “full” and still be ravenously hungry. As a ketonian, I reach the point of “enough” at what feels like no more than a half-full stomach.
The experience of satiety reminds me of a difference pointed out to me by a French professor. She said that Americans tend to say, “I’m full,” whereas she grew up saying the French equivalent for, “I’ve had enough.” This linguistic difference may reflect a difference in eating patterns. I am old enough to remember that the excessively large plates of food seen in American restaurants didn’t start appearing until after people started following the dietary recommendations. But French meals are satisfying with much smaller portions (or used to be, anyway), because they are much heavier on the meat and fat, and much less loaded with grains, starches, and sugar.