Terrib
I call it formula also. I've been using Jevity 1.5 but my new medical supply company shipped me one case of IsoSource 1.5 to try out. Comparing the two online indicates that Jevity has more fiber: 22g/L than Iso 8g/L and better fiber: FOS rather than guar gum. But I may mix and match a little as the more different types of fiber the better.
Plus I have "real food" everynight, the same dinner as my wife makes for herself, that I throw into the Vitamix and put down the tube.
Charm