As a 50-year binge eater, my stomach was certainly stretched--as documented by the photo of my large hiatal hernia.
I don't think my stomach ever shrank during my down-yo-yo cycles; I always needed large salads and lots of whole fruit to delay relapses to binge behavior.
I think IF has worked for me precisely because it allows me to eat to satiation if my (80% of daily food) main meal has a fruit-salad-meat/veg structure. Eating more but smaller meals literally drives me nuts.
One difference I've noticed on whole foods and IF is that I do notice satiation signals now, which I never noticed before no matter how much I ate. In fact, in the past my "hunger" signals were probably GI discomfort from SAD foods recently eaten. Now that I have no GI discomfort overnight or when I wake up, it's easy to delay eating until it's convenient and I get "enough" signals on each course--by that I mean I may not finish my salad but still want meat. In the past month or two I may have experienced earlier satiation signals, since if I started with meat I canceled the salad a few times.
EDIT: I don't think I made my point clear enough--I don't think meal volume itself determines body fat because my meal volume was consistent while the mix of foods changed and I ate meals more frequently.