More recently, I've been mostly eating until I feel well-nourished and then stopping. Well-nourished is a pleasant feeling in my lower right abdomen. It isn't on the hungry-fed-full-overfed-stuffed continuum which correlates excellently with not feeling hungry for quite a while. Making that change from my previous habit of eating until I felt full enough that eating more was no longer a pleasure was a surprising amount of work--enough that I'm not sure I can call it an easy default, though it seems pretty close to a habit now. It might be enough work that it doesn't count as an easy default, though it wouldn't surprise me if some people (probably not the majority) start out eating that way.
I'm surprised at how much less I eat-- a half pound of cheese (with some bread or salad) hangs round for an unspecified number of meals instead of evaporating in a meal or two. Likewise for a pound of meat.
My weight is the same.
I might be weird that way-- my impression is that there are a lot of people whose weight swings 10 or 20 pounds plus and minus without them doing anything obvious to change their eating or exercise. My weight has never done that.