As I’ve mentioned before, for me satiety is a feeling of “enough; I don’t want any more,” a very different feeling from being full. The words "satiety’ and “satisfaction” are derived from the Latin word satis ‘enough’, and embarking on a ketogenic diet was the first time in decades that I had experienced the sensation of not wanting more food. Plenty of room for it, but didn’t need or want it. That was a weird experience for a carb-burner, let me tell you!
I find that, since there is room in my belly for more food, I can eat past the point of satiety, but when I do so, it is always for emotional reasons. So I try to have fatty, low-carb snacks handy, so I’m not tempted to eat the cornbread and other goodies people leave lying around the kitchen at my house. (If I lived alone, that would not even be a problem; it wouldn’t be there.)
I did find that for a while after going full-bore keto, I kept eating at my usual quantity level. Looking back, I wonder if that was even a problem; perhaps my body needed those extra calories to help re-regulate itself. I do remember that my first experience of not being able to finish a meal came as quite a shock. I might have thought something was wrong, but at the time I was watching a lot of lectures by Dr. Phinney on YouTube, and so what I found myself thinking was, “Oh! This must be that satiety thing he talks about.” So I wrapped the half-plate of food remaining, put it into the fridge, and didn’t finish it until supper, many hours later.
So the issue of how much to eat, in my case, breaks down into two problems: (1) listening to my body for cues as to the actual quantity it wants (on some days, more; on other days, less), and (2) how to deal with my need to put stuff in my mouth so I won’t have to deal with my feelings. Dr. Robert Cywes says that for that purpose he always keeps a cup of coffee handy, which works well for me, too; and I find that having something low-carb to munch on means that if I do eat past the satiety point, the extra food is at least not raising my blood sugar and insulin. Also, I don’t snack to nearly the same degree as I would if it were carbs.
My big fear is of bingeing on carbohydrates. Interestingly, although I would describe myself as a sugar/carb addict, my experience since going keto suggests that the satiety engendered by a ketogenic diet blunts the urge to binge. So whereas, in my carb-burning days, I used to eat whole giant economy-sized bags of candy or a couple of dozen doughnuts at one sitting (all the while bemoaning my lack of will power), these days when I yield to temptation, I tend to be content with just one piece of cornbread, or half a bagel (or at most just one whole bagel). The thought of wildly consuming carbohydrates, even sugar, is somehow a lot less powerful on keto.