I have never eaten past satiety. Instead I split into 2 meals, and ate to satiety at both, which seems to have effectively doubled my caloric load (plus drinking zorntini’s every now and then).
I did this for a week straight and didn’t gain an ounce, despite eating between 3-4000 calories each day (although some I did lower back to ‘normal’ because I forgot to eat/wasn’t hungry/etc).
I am doing this to effectively raise my metabolism as shown in overfeeding experiments where they found their BMR rose to match calories consumed.
So far this has not led to any weight gain - which means it is likely working. This means more of my energy is being used for various bodily processes like muscle growth, cell replacement, etc
I then pair it with fasting for as long as I can - whether the high BMR lasts through the fast, I have no idea. But feasting beforehand DOES help me fast for longer periods, and then I get the benefits of autophagy.
For me it is just that I had stalled for roughly 3 months, and I had clearly gotten into a rut of not caring much about food and being overly lazy and eating a small amount and stopping when I could have (and maybe should have) eaten some more (basically undereating) which wasn’t helping with the stall at all.
However others may have different reasons for doing it, and different ways of doing it. You can say feasting means making sure you’re not undereating (in which case you can just call it feeding), or you can say you want to split it into two meals and eat to satiety at both to increase caloric load for other reasons, like switching up your routine and help break out of a rut. It really depends.
EDIT: I should note though that I would never recommend stuffing yourself full of food. Throughout feasting (and fasting) I’ve felt full of energy, spontaneous walks, very good mood, etc. I took it to mean what I was doing was okay (and it seems that’s true). If you tried the same and felt overfull, bad mood, sick, etc then I’d say it definitely is not worth continuing.
Also my extra calories are coming from fat and the extra carb amount I had to deal with (I usually eat under 10 or 15g NET so there’s room to work) but mostly fat, yeah.