As as teenager on school vacation days, I davened at a shul in which the a couple of retirees took it upon themselves to fetch bagels and assorted fillings for the weekday morning minyan to boost attendance (and they’d clean up afterwards).
When he could, the rav of the shul would stick around and have his morning coffee with those who weren’t hurrying off to work. Looking back, it was a pleasant, relaxed way for the rav to interact informally with about a dozen of his congregants.
A number of them had the “minhag” of scooping out the bagel innards which they justified as a calorie-saving move.
I’m not sure how many calories were actually saved after adding the fillings (butter, cream cheese, egg salad, etc.), but that’s the only time I can recall seeing people do that.